Idaho Car Loan Calculator

Buying a car in Idaho is not a Title Ad Valorem Tax problem, and it is not a mystery local “car tax” layered on every county. Idaho charges a statewide 6 percent sales tax at a dealership or a matching 6 percent use tax on a private or out-of-state purchase. That rate is in Idaho Code §§ 63-3619 and 63-3621. The Idaho Transportation Department then collects a $14 state title, an age-based passenger registration of $69, $57, or $45, and a $1.25 EMS add-on. Some cities add a local option tax. None of those figures come from a bank-rate survey.

This guide explains how an Idaho auto loan calculator should turn those official rules into a monthly payment. Every dollar and percent below is from the Idaho State Tax Commission, the Idaho Transportation Department, the Idaho Code, or the Federal Reserve’s G.19 Consumer Credit release. Industry surveys are not used. If a public agency does not publish a number — including your city’s local option tax and your county’s title admin — the calculator leaves it to you. You will see a $38,000 new-car example at the official 60-month bank average of 7.14 percent, a cash-versus-roll comparison, a used-dealer trade-in, a private-party use-tax deal, and the 90-day new-resident rule.

What Makes Idaho Different From Georgia and From a “Just 6%” Shortcut

Shoppers who moved from Georgia often look for Title Ad Valorem Tax. Idaho still uses ordinary sales and use tax. Copying a 7 percent TAVT line onto a $38,000 Idaho deal produces $2,660. That number is wrong here. Six percent of $38,000 is $2,280.

The other shortcut is to treat 6 percent as the only number that matters. Freight to the seller, factory options, mandatory warranties, document fees, dealer labor that is part of the sale, and auction or buyer fees are in the sales price even when they are not separately stated. Optional service contracts, finance charges, optional insurance, and government title or registration fees (up to the government amount) are out if separately stated. Leaving a $500 doc fee out of the 6 percent base understates tax by $30.

Important: Idaho is sales tax and use tax, not Title Ad Valorem Tax. Do not copy a Georgia TAVT line of $2,660 onto a $38,000 Idaho deal. State tax on that price is $2,280. Document fees are in the 6 percent base. Cash down does not reduce the tax. Rolling the tax into the loan finances the tax; it does not change the tax.

A third Idaho rule that surprises people is the trade-in. A qualifying trade reduces taxable sales price on a dealer sale if the property goes into the seller’s resale inventory, is identified in the sales documents at the time of sale, and is one transaction (IDAPA 35.01.02.044). The trade-in does not have to be a vehicle. The Tax Commission has said even a horse can qualify if it is inventoried for resale. A driveway sale has no dealer inventory. Private-party use tax is 6 percent of the purchase price. There is no dealer-style credit.

Manufacturer rebates follow a similar split. A rebate reduces the taxable price only if it is paid to the dealer and subtracted from the vehicle price. If you take the cash, the taxable price does not drop. Cash down and insurance settlements never reduce the taxable price. Those dollars change how you pay. They do not change what Idaho taxes.

There is no cooling-off period on a dealership purchase. Lemon Law is Idaho Code §§ 48-901 through 48-912. It covers new motor vehicles and requires written notice. It does not add a titling stamp. The Idaho Credit Code in title 28 governs contracted delinquency charges. This guide does not invent a default late-fee dollar.

References:

• Idaho Code §§ 63-3619, 63-3621, 63-3622R, 63-3623 — sales and use tax
• IDAPA 35.01.02.044 — trade-in allowance
• Idaho Tax Commission — sales and use online guide
• Tax Commission — dealer sales price
• Publications EPB00060 and EPB00778

Official Idaho Fees You Can Rely On (2026)

These costs are published by the Tax Commission, the Idaho Transportation Department, and the Idaho Code. A responsible calculator uses them as defaults. It does not invent an average doc fee, a statewide local option rate, or a used-car APR.

Item	Official amount	Source
State sales / use tax	6% of sales price after qualifying trade-in	Idaho Code §§ 63-3619, 63-3621
Local option tax	User-entered; default $0	Some cities levy LOT. Not statewide.
State title	$14	ITD titles page (admin fee + $14)
County title admin	Varies; default $0	ITD county table (Ada $7 → $21 total)
Passenger registration, 1–2 years old	$69	ITD; Idaho Code title 49; ≤ 8,000 lbs
Passenger registration, 3–6 years old	$57	ITD
Passenger registration, 7 years and older	$45	ITD
EMS add-on	$1.25	ITD
Electric vehicle extra	$140 per year	Idaho Code § 49-457 (not neighborhood EVs)
Plug-in hybrid extra	$75 per year	Idaho Code § 49-457
New plates	$3.75 per plate	ITD fact sheet; user-entered if shown
Documentary fee	No statutory cap; taxable; default $0	Tax Commission dealer sales-price page
Lemon Law fee	None as a titling add-on	Idaho Code §§ 48-901 et seq.
APR prefill (new car)	7.14%	Fed G.19 60-month bank, Q2 2026

County registration admin and highway-district extras stay user-entered at $0. Duplicate title is $14 extra, a late-title penalty is $20, and a rush title is $26 extra (ITD). Those are not first-title defaults on a clean dealer deal.

Example 1: Official title on a clean Ada County deal

Scenario: You buy a new car in Boise and title it in Ada County. ITD’s state title is $14. Ada’s county title admin is $7.

State title (ITD): $14.00 Ada County title admin: $7.00 Total title: $21.00

The calculator starts at $14 and lets you type the county admin. Treating every Idaho title as a flat $14 without disclosing the ITD county table understates Ada and overstates a county that charges nothing.

Example 2: Official title in a county with no admin add-on

Scenario: Same car, titled in Bannock County. ITD lists Bannock title admin as $0.

State title (ITD): $14.00 Bannock County title admin: $0.00 Total title: $14.00

The statewide official number is still $14. The county line is what changes. That is why the calculator does not hard-code $21 for every Idaho buyer.

References:

• ITD — vehicle titles (state $14 and county admin table)
• ITD — vehicle registrations
• Idaho Code § 49-202 (department fees); § 49-457 (EV / plug-in hybrid)

How Idaho Sales and Use Tax Builds the Taxable Price

The 6 percent rate is the easy part. The tax base is where deals diverge. The Tax Commission’s dealer sales-price page and IDAPA 35.01.02.044 decide what is in and what is out. Evidence of tax paid, or of an exemption, is required before the county will title the vehicle (Idaho Code § 63-3623(l)).

Dealer sales — new or used

On a licensed dealer deal, Idaho sales tax is 6 percent of sales price after a qualifying inventory trade-in. Sales price includes the vehicle, freight to the seller, options, mandatory warranties, and documentary fees. A manufacturer rebate reduces that price only when it is paid to the dealer and subtracted from the vehicle price. Cash down does not.

Example 1: New dealer, no trade, no rebate, no extra doc

Scenario: A $38,000 new car at an Idaho franchise store. Extra doc is $0. No trade. No rebate.

Selling price: $38,000.00 Taxable documentary fee: $0.00 Qualifying trade-in: $0.00 Dealer-paid rebate: $0.00 Taxable base: $38,000.00 State sales tax (6%): $38,000.00 × 0.06 = $2,280.00

That $2,280 is the official state tax on the worked example later in this guide. Local option tax, if your city charges one, sits on top. The calculator does not invent a city rate.

Example 2: Same dealer deal with a $500 doc fee

Scenario: The store adds a $500 documentary fee that is part of the sale.

Selling price: $38,000.00 Taxable documentary fee: $500.00 Taxable base: $38,500.00 State sales tax (6%): $38,500.00 × 0.06 = $2,310.00

The extra $30 is why a calculator that leaves doc fees out of the 6 percent base is not following the Tax Commission. Idaho has no statutory dollar cap on the doc fee. The default in this calculator is $0 so that a fee already inside the sticker is not taxed twice.

Used dealer with a qualifying trade-in

A used-dealer sale uses the same 6 percent rate. The difference is the inventory trade-in. If the store takes your old vehicle (or other property) into resale inventory and lists it on the bill of sale in the same transaction, the allowance reduces taxable sales price.

Example 1: Used dealer, $18,500 price, $3,000 inventory trade

Scenario: This is official Example C from the Idaho brief. The trade is placed in inventory and listed on the bill of sale.

Selling price: $18,500.00 Inventory trade-in: -$3,000.00 Taxable base: $15,500.00 State sales tax (6%): $15,500.00 × 0.06 = $930.00

There is no official used-car APR. G.19 does not publish one. The calculator will not invent a used rate. You can illustrate the payment at 7.14 percent only if you label it as the official 60-month new-car bank rate and then type your actual used quote.

Example 2: Same numbers if the “trade” is not inventoried

Scenario: The buyer still hands the dealer a $3,000 vehicle, but the property is not taken into resale inventory or is not identified in the sales documents.

Selling price: $18,500.00 Non-qualifying trade: $0.00 tax credit Taxable base: $18,500.00 State sales tax (6%): $18,500.00 × 0.06 = $1,110.00

The $3,000 still reduces how much you finance. It does not reduce Idaho tax unless the inventory and documentation tests are met. That $180 gap is the difference between a qualifying trade and a handshake.

Private-party use tax

A casual sale is use tax, still 6 percent, still collected before title. There is no dealer inventory, so there is no trade-in reduction. Manufacturer rebates do not apply.

Example 1: Private sale of the same $18,500 car

Scenario: Official Example D. You buy from a neighbor for $18,500.

Purchase price: $18,500.00 Dealer inventory trade-in: n/a Use tax (6%): $18,500.00 × 0.06 = $1,110.00 State title: $14.00 County title admin: user-entered Age-based registration: $69 / $57 / $45 EMS: $1.25

Use tax is $180 higher than the used-dealer Example C because the $3,000 trade does not exist as a tax credit on a driveway sale.

Example 2: Private sale with cash down and a “trade”

Scenario: Same $18,500 neighbor car. You pay $4,000 cash and give the seller your old motorcycle, which you both call a $2,000 trade.

Purchase price: $18,500.00 Cash down (does not reduce tax): $4,000.00 Informal “trade” (no dealer inventory): $0 tax credit Use tax still: $18,500.00 × 0.06 = $1,110.00

Cash and a casual swap change what you write on a check. They do not change Idaho use tax. Title, county admin, the age-based tag, and EMS still apply.

References:

• Idaho Code §§ 63-3619 (sales tax), 63-3621 (use tax), 63-3623(l) (evidence before title)
• IDAPA 35.01.02.044 — trade-in identified in the sales documents
• Tax Commission dealer sales-price page — what is in and out of sales price

New Residents, the 90-Day Presumption, and Credit for Tax Already Paid

Idaho does not offer a reduced “new resident rate.” It offers an exemption or a credit, depending on when and where you bought the car.

Idaho Code § 63-3621(12) exempts a personally owned vehicle that you acquired in another state while you were a resident there and that you actually used in a substantial way outside Idaho. If you acquired it less than 90 days before entering Idaho, the law presumes you acquired it for Idaho use. Credit is available for sales or use tax already paid to another U.S. state. Nonresidents have a 90-day use limit under § 63-3621(11). Dealer sales to nonresidents who will title elsewhere are a separate exemption path under § 63-3622R. New residents must title and register in Idaho within 90 days (ITD).

Example 1: New resident who owned the car for years out of state

Scenario: You lived in Oregon, bought the car there 18 months ago, used it as your daily driver, and now move to Idaho. You still owe Idaho title, registration, and EMS. You do not owe Idaho use tax if § 63-3621(12) is met.

Idaho sales / use tax: $0.00 (exemption) State title: $14.00 Passenger registration (age-based): $69 / $57 / $45 EMS: $1.25 County title / reg admin: user-entered

Bring proof of out-of-state ownership and use. The county will not title without evidence of tax paid or exemption (§ 63-3623(l)).

Example 2: Bought out of state 40 days before the move, or you already live in Idaho

Scenario: You signed for a $38,000 car in Utah 40 days before you entered Idaho, or you already live in Boise and buy the same car on a weekend trip. The 90-day presumption applies, or you are an Idaho resident buying out of state. Tax is 6 percent of price, minus credit for tax paid to the other state.

Idaho tax before credit: $38,000.00 × 0.06 = $2,280.00 Tax paid to the other state (user-entered proof): for example $1,900.00 Idaho tax after credit: $380.00

If the other state charged more than Idaho’s 6 percent, the credit can zero the Idaho tax. It cannot create a refund. The calculator applies that credit only on the under-90-days / Idaho-resident out-of-state channel.

Important: The 90-day clock is about when you acquired the vehicle relative to entering Idaho, not about a grace period to skip tax. New residents still title and register within 90 days. Buying as an Idaho resident on the other side of the state line is not the new-resident exemption.

References:

• Idaho Code § 63-3621(12) — new-resident exemption and 90-day presumption
• Idaho Code § 63-3621(11) — nonresident 90-day use limit
• Idaho Code § 63-3622R — dealer sales to nonresidents who will title elsewhere
• ITD — new residents title and register within 90 days

Title, Registration, EMS, Plates, and the EV / Plug-In Charges

ITD’s title page describes the state portion as an admin fee plus $14. Counties add their own title admin. Registration for a passenger vehicle at or under 8,000 pounds is age-based: $69 if the vehicle is one or two years old, $57 at three through six years, and $45 at seven years and older. EMS is $1.25. New plates are $3.75 per plate on the ITD fact sheet. Those plate dollars stay user-entered so a transfer is not charged as a new plate by default.

Example 1: New two-year-old passenger car, no county extras

Scenario: The official worked example. One-to-two-year-old passenger vehicle. County title admin $0. No new-plate line typed in.

State title: $14.00 County title admin: $0.00 Passenger registration (1–2 yrs): $69.00 EMS: $1.25 Title and registration subtotal in the calculator: $84.25 Brief Example A (title + tag only, EMS omitted in the brief): $83.00

The brief’s $38,000 payment example uses $14 + $69 = $83 and does not add EMS. The calculator still applies the official $1.25 EMS line because ITD publishes it. On a $36,563 loan the extra $1.25 changes the payment by two cents.

Example 2: Seven-year-old car in Ada County with two new plates

Scenario: A 2018 passenger car titled in Ada County. You need two new plates.

State title: $14.00 Ada County title admin: $7.00 Passenger registration (7+): $45.00 EMS: $1.25 Two new plates × $3.75: $7.50 County / highway-district extra: user-entered Title and tag subtotal before highway-district: $74.75

Age dropped the registration from $69 to $45. County admin and plates pushed the total back up. That is why vehicle age is a dropdown and county lines stay in your hands.

Electric vehicles and plug-in hybrids

Idaho Code § 49-457 adds an annual extra of $140 on electric vehicles that are not neighborhood EVs, and $75 on plug-in hybrids. Those are ownership costs. They are not a first-title stamp and they are not part of the loan payment. Do not apply the $140 charge to a conventional hybrid. Do not stack $140 and $75 on the same vehicle.

Example 1: Battery-electric car

Scenario: A new battery-electric passenger car. First-year registration is still the age-based $69 plus EMS $1.25. The § 49-457 extra is $140 per year as an ownership note.

Passenger registration (1–2 yrs): $69.00 EMS: $1.25 EV extra (§ 49-457): $140.00 / year (shown as ownership; not in the monthly loan)

The calculator can show the $140 line when you mark the vehicle as electric. It does not add $140 to amount financed or to cash due at signing.

Example 2: Conventional hybrid versus plug-in hybrid

Scenario: One household is looking at a regular gasoline hybrid. The other is looking at a plug-in hybrid.

Conventional hybrid: § 49-457 extra: $0.00 (do not apply the $140 EV fee) Plug-in hybrid: § 49-457 extra: $75.00 / year (ownership note; not in the loan)

The $140 figure is for electric vehicles that are not neighborhood EVs. Applying it to a conventional hybrid is one of the mistakes the official brief tells a calculator not to make.

References:

• ITD vehicle registrations and titles pages — $69 / $57 / $45, EMS $1.25, title $14, county table
• Idaho Code § 49-457 — EV $140 / year; plug-in hybrid $75 / year
• ITD fact sheet — $3.75 per plate

Official Auto Loan Rates and the Payment Formula

Idaho does not publish a statewide official APR series. The official U.S. series is the Federal Reserve G.19 Consumer Credit release. The current release used in this guide is dated 7 August 2026 and reports June / second-quarter 2026 data. Bank rates in that table are unweighted averages of each bank’s most common rate in the first calendar week of the middle month of the quarter. They are not origination-weighted and they are not Idaho-specific.

Series	Rate	Period
Commercial-bank 60-month new-car	7.14%	Q2 2026
Commercial-bank 72-month new-car	6.97%	Q2 2026
Finance-company new-car (amount-weighted)	6.1% (Q1) / 6.08% (Mar 2026)	FRED RIELPCFANNM

The calculator prefills 7.14 percent only as the G.19 60-month new-car bank average for a new vehicle. It amortizes at whatever rate you type. G.19 does not publish a used-car APR. There is no official government APR-by-FICO table. Credit-score presets do not belong in this form.

Do not treat the 72-month bank print sitting below the 60-month print as proof that longer terms are cheaper. G.19 says that figure is the banks’ “most common” quoted mix, not a term premium. Sixty months is a reasonable default because that is the series G.19 publishes. Eighty-four months is not an official default.

For context only — not as calculator defaults — the effective federal funds rate was 3.63 percent on the H.15 release for 21–27 August 2026, and bank prime was 6.75 percent.

The payment math is standard amortization. Treat the entered rate as a nominal annual rate, compounded monthly. Monthly rate i equals the annual rate divided by 12. For amount financed P over n months:

Monthly payment M = P × [ i (1 + i)ⁿ ] ÷ [ (1 + i)ⁿ − 1 ]

If the rate is zero, M is simply P divided by n. The monthly payment is rounded half-up to the cent. The last payment clears the residual balance. Totals come from that schedule. This is an estimate, not a Regulation Z APR solution and not a lender offer.

Amount financed is roughly (price − down − trade + trade payoff − rebate) plus any tax, fees, and doc you roll, plus financed GAP or warranty. Cash due is down plus any tax, fees, and doc you do not roll. GAP and warranty, if financed, add to principal. Separately stated optional warranties stay out of the sales-tax base.

Example 1: Why 60 months is the default term

Scenario: A website advertised 84 months.

Official G.19 series: 60-month new-car bank at 7.14% Prefill term: 60 months 84 months: not an official default

You may type 72 or 84 if your lender offers it. The form will not pretend 84 is a government standard.

Example 2: Used-car APR

Scenario: You finance the $18,500 used dealer car from Example C.

Official used-car APR on G.19: none Optional illustration only: 7.14%, labeled as the official 60-month new-car bank rate

Type your lender’s used quote. A commercial “used average” is not an official figure.

References:

• Federal Reserve G.19 — 7 August 2026 release; 60-month bank 7.14%
• Federal Reserve H.15 — effective federal funds 3.63%; prime 6.75%
• FRED series RIELPCFANNM — finance-company new-car rate

How the Idaho Auto Loan Calculator Walks Through a Deal

The form has three input sections and a live results panel. Section 1 is the purchase channel, price, documentary fee, down payment, trade, payoff, dealer-paid rebate, city local option tax, and any credit for tax already paid to another state. Section 2 is Idaho fees: vehicle age ($69 / $57 / $45), county title and registration admin, new plates, roll-in flags, financed GAP or warranty, and the § 49-457 EV or plug-in ownership notes. Section 3 is financing. APR prefills at 7.14 percent. Term prefills at 60 months.

1. Choose the purchase channel. That choice decides whether trade and rebate reduce tax, whether use tax applies, and whether the new-resident exemption or the out-of-state credit is available.
2. Enter price and any taxable doc fee. Doc is in the 6 percent base.
3. Enter down, trade, payoff, and rebate. Down never changes tax. Trade and rebate change tax only on the channels the statutes allow.
4. Enter city local option tax if your city charges one. Leave $0 if it does not.
5. Set vehicle age. Add county title admin from the ITD table if your county charges it.
6. Decide whether to roll tax and fees. Rolling does not change the tax or the fee. It changes cash today and interest over the life of the loan.
7. Confirm APR and term. Replace 7.14 percent with your lender quote, especially on a used car.

The results panel lists each tax and fee on its own row, with notes for dealer trades, private-party use tax, the new-resident exemption, and the under-90-days credit. A footer reminds you the figure is an estimate, not a TILA disclosure.

Match the channel to the deal. Leaving the form on “New Idaho dealer” while you buy from a neighbor would still offer a trade-in tax credit that a private sale does not have. The next section works the $38,000 roll-versus-cash paths with official numbers.

Complete Official Worked Examples on a $38,000 New Car

Assumptions for both paths: new Idaho dealer, extra doc $0, no trade, no rebate, no GAP or warranty, 6 percent state tax, no local option tax, state title $14, county admin $0, passenger registration for a one-to-two-year-old vehicle $69, APR equal to the official G.19 60-month bank rate of 7.14 percent, 60 months, payment rounded half-up to the cent, last payment clears the residual. These are the brief’s Example A and Example B.

Example A: Tax, title, and tag rolled into the loan

Scenario: Price $38,000. Down payment $3,800 (10 percent). You finance the tax and the $14 + $69 government fees.

State sales tax: $38,000.00 × 0.06 = $2,280.00 State title: $14.00 Passenger registration (1–2 yrs): $69.00 Amount financed: $38,000 − $3,800 + $2,280 + $14 + $69 = $36,563.00 Monthly payment (7.14%, 60 mo): $726.41 Cash due at signing: $3,800.00 Total of payments: $43,584.52 Total interest: $7,021.52

Add your county’s title or registration admin if the ITD table shows a charge. The calculator also applies official EMS of $1.25, which the brief’s Example A omitted. With EMS, amount financed is $36,564.25 and the monthly payment is $726.43.

Example B: Same deal, tax and fees paid in cash

Scenario: Same $38,000 car, same $3,800 down, same 7.14 percent and 60 months. You pay the $2,280 tax and the $14 + $69 fees at signing instead of rolling them.

Amount financed: $38,000 − $3,800 = $34,200.00 Monthly payment (7.14%, 60 mo): $679.46 Cash due at signing: $3,800 + $2,280 + $14 + $69 = $6,163.00 Total of payments: $40,767.75 Total interest: $6,567.75 Rolling versus cash: Extra interest if you roll: $453.77 Less cash at signing if you roll: $2,363.00

The tax is $2,280 either way. Rolling does not create a discount. It trades $2,363 of cash today for $453.77 of extra interest over five years at the official 7.14 percent illustration rate.

Those four payment figures — $726.41 rolled, $679.46 cash, totals of $43,584.52 and $40,767.75 — are the official $38,000 / 10 percent down / 60-month / 7.14 percent Idaho worked example. They use half-up rounding to the cent and a last payment that clears the residual. They are not a lender quote.

Common Questions and Easy Mistakes

Does cash down lower Idaho sales tax? No. It lowers amount financed and cash due, not the taxable price. Insurance settlements do not change the tax either.

Is there a Lemon Law stamp? No. Idaho Code §§ 48-901 through 48-912 create a warranty remedy. They do not add a titling fee. There is also no cooling-off period on a dealership purchase.

What if my city has a local option tax? Enter the dollar amount. LOT is not a statewide add-on, so the default is $0.

I am moving from another state. Do I pay 6 percent again? If you acquired the vehicle while living in the other state and used it there more than 90 days, § 63-3621(12) can exempt it. Under 90 days, or an Idaho resident buying out of state: 6 percent minus credit for tax paid elsewhere. Title and register within 90 days.

Does the $140 electric fee apply to my hybrid? Only a plug-in hybrid takes a § 49-457 extra, and that extra is $75 per year, not $140. Conventional hybrids and neighborhood EVs do not take $140. Neither extra is in the loan payment.

Why is 7.14 percent on a used car? Only as an illustration of the official new-car bank average. G.19 has no used-car series. Type your lender’s used quote.

Where the Numbers Come From and How They Stay Current

Sales and use tax come from Idaho Code §§ 63-3619, 63-3621, 63-3622R, and 63-3623, from IDAPA 35.01.02.044, and from the Tax Commission’s online guide and dealer sales-price page, including publications EPB00060 and EPB00778. Title, registration, EMS, plates, and the county admin table come from ITD’s titles and registrations pages and from Idaho Code title 49, including § 49-202 and § 49-457. Lemon Law is §§ 48-901 and following. APR context is Federal Reserve G.19 (7 August 2026 release), H.15, and FRED RIELPCFANNM.

The access date in the official brief is 29 August 2026. This calculator does not scrape live Tax Commission or ITD tools. When a statute or ITD table changes, update from the new official publication — not from a dealer worksheet or a commercial rate survey. Doc fees, city LOT, and county admin stay user-entered so the form does not invent them.

What to Take to the Desk

Idaho’s auto loan math is a 6 percent sales or use tax on a carefully defined price, plus ITD title, age-based registration, and EMS, plus whatever your city and county add. It is not Georgia TAVT, not a used-car APR table, and not an 84-month government standard.

On a $38,000 new Idaho dealer car with 10 percent down, no extra doc, no trade, and no city LOT, state tax is $2,280. Roll tax with the $14 title and $69 tag at the official 7.14 percent 60-month bank average and the estimated payment is $726.41 with $3,800 cash due. Pay tax and those fees in cash and the estimate is $679.46 a month and $6,163 due at signing. Rolling costs about $454 extra in interest and saves $2,363 at signing.

Match the channel to the deal, keep doc fees in the tax base, credit only inventory trades, honor the 90-day new-resident line, add county admin from the ITD table, and leave EV extras in the ownership column. Then replace 7.14 percent with your lender’s quote. The result is an estimate — not a contract.

Complete official sources (access date 29 August 2026):

• Idaho Code §§ 63-3619, 63-3621, 63-3622R, 63-3623 — sales and use tax
• Idaho Code § 49-457 — electric and plug-in hybrid extras; § 49-202 — department fees
• Idaho Code §§ 48-901 et seq. — lemon law (no titling stamp)
• IDAPA 35.01.02.044 — trade-in
• Idaho Tax Commission — sales and use online guide
• Tax Commission — dealer sales price; publications EPB00060, EPB00778
• ITD vehicle registrations
• ITD vehicle titles (county admin table)
• Federal Reserve G.19 (7 August 2026); H.15; FRED RIELPCFANNM

This article and the Idaho Auto Loan Calculator are estimates for education only. They are not a Regulation Z or TILA disclosure, not a lender offer, and not tax or legal advice. Confirm current rates and fees with the Idaho State Tax Commission, the Idaho Transportation Department, your city and county, and the APR in your contract. Figures above follow the official Idaho brief as of 29 August 2026 and were not taken from Experian, Edmunds, Bankrate, CarEdge, or credit-union rate sheets.