Loan
Summary
Monthly payment
- Total interest
- $4,631.10
- Total of payments
- $29,631.10
Estimate only — not a financing offer. Excludes taxes, fees, and any insurance or add-ons rolled into a real contract.
Amortization schedule
| Month | Payment | Principal | Interest | Balance |
|---|---|---|---|---|
| 1 | $493.85 | $350.10 | $143.75 | $24,649.90 |
| 2 | $493.85 | $352.11 | $141.74 | $24,297.79 |
| 3 | $493.85 | $354.14 | $139.71 | $23,943.65 |
| 4 | $493.85 | $356.17 | $137.68 | $23,587.48 |
| 5 | $493.85 | $358.22 | $135.63 | $23,229.26 |
| 6 | $493.85 | $360.28 | $133.57 | $22,868.98 |
| 7 | $493.85 | $362.35 | $131.50 | $22,506.63 |
| 8 | $493.85 | $364.44 | $129.41 | $22,142.19 |
| 9 | $493.85 | $366.53 | $127.32 | $21,775.66 |
| 10 | $493.85 | $368.64 | $125.21 | $21,407.02 |
| 11 | $493.85 | $370.76 | $123.09 | $21,036.26 |
| 12 | $493.85 | $372.89 | $120.96 | $20,663.37 |
| 13 | $493.85 | $375.04 | $118.81 | $20,288.33 |
| 14 | $493.85 | $377.19 | $116.66 | $19,911.14 |
| 15 | $493.85 | $379.36 | $114.49 | $19,531.78 |
| 16 | $493.85 | $381.54 | $112.31 | $19,150.24 |
| 17 | $493.85 | $383.74 | $110.11 | $18,766.50 |
| 18 | $493.85 | $385.94 | $107.91 | $18,380.56 |
| 19 | $493.85 | $388.16 | $105.69 | $17,992.40 |
| 20 | $493.85 | $390.39 | $103.46 | $17,602.01 |
| 21 | $493.85 | $392.64 | $101.21 | $17,209.37 |
| 22 | $493.85 | $394.90 | $98.95 | $16,814.47 |
| 23 | $493.85 | $397.17 | $96.68 | $16,417.30 |
| 24 | $493.85 | $399.45 | $94.40 | $16,017.85 |
| 25 | $493.85 | $401.75 | $92.10 | $15,616.10 |
| 26 | $493.85 | $404.06 | $89.79 | $15,212.04 |
| 27 | $493.85 | $406.38 | $87.47 | $14,805.66 |
| 28 | $493.85 | $408.72 | $85.13 | $14,396.94 |
| 29 | $493.85 | $411.07 | $82.78 | $13,985.87 |
| 30 | $493.85 | $413.43 | $80.42 | $13,572.44 |
| 31 | $493.85 | $415.81 | $78.04 | $13,156.63 |
| 32 | $493.85 | $418.20 | $75.65 | $12,738.43 |
| 33 | $493.85 | $420.60 | $73.25 | $12,317.83 |
| 34 | $493.85 | $423.02 | $70.83 | $11,894.81 |
| 35 | $493.85 | $425.45 | $68.40 | $11,469.36 |
| 36 | $493.85 | $427.90 | $65.95 | $11,041.46 |
| 37 | $493.85 | $430.36 | $63.49 | $10,611.10 |
| 38 | $493.85 | $432.84 | $61.01 | $10,178.26 |
| 39 | $493.85 | $435.33 | $58.52 | $9,742.93 |
| 40 | $493.85 | $437.83 | $56.02 | $9,305.10 |
| 41 | $493.85 | $440.35 | $53.50 | $8,864.75 |
| 42 | $493.85 | $442.88 | $50.97 | $8,421.87 |
| 43 | $493.85 | $445.42 | $48.43 | $7,976.45 |
| 44 | $493.85 | $447.99 | $45.86 | $7,528.46 |
| 45 | $493.85 | $450.56 | $43.29 | $7,077.90 |
| 46 | $493.85 | $453.15 | $40.70 | $6,624.75 |
| 47 | $493.85 | $455.76 | $38.09 | $6,168.99 |
| 48 | $493.85 | $458.38 | $35.47 | $5,710.61 |
| 49 | $493.85 | $461.01 | $32.84 | $5,249.60 |
| 50 | $493.85 | $463.66 | $30.19 | $4,785.94 |
| 51 | $493.85 | $466.33 | $27.52 | $4,319.61 |
| 52 | $493.85 | $469.01 | $24.84 | $3,850.60 |
| 53 | $493.85 | $471.71 | $22.14 | $3,378.89 |
| 54 | $493.85 | $474.42 | $19.43 | $2,904.47 |
| 55 | $493.85 | $477.15 | $16.70 | $2,427.32 |
| 56 | $493.85 | $479.89 | $13.96 | $1,947.43 |
| 57 | $493.85 | $482.65 | $11.20 | $1,464.78 |
| 58 | $493.85 | $485.43 | $8.42 | $979.35 |
| 59 | $493.85 | $488.22 | $5.63 | $491.13 |
| 60 | $493.95 | $491.13 | $2.82 | $0.00 |
What auto loan amortization is
A level, fixed payment that fully pays off principal plus interest by the end of the term.
The CFPB puts it simply: “a percentage of your monthly payment is applied to the principal and to the interest.” The payment amount stays constant, but the mix shifts every month — early on it’s mostly interest, and by the end it’s almost all principal. The amortization schedule is the row-by-row table of that split: payment number, interest portion, principal portion, and remaining balance.
The amortization formula
Every fixed-payment loan comes from one equation.
- M
- monthly payment
- P
- amount financed (principal)
- r
- periodic rate = APR ÷ 12
- n
- number of payments (months)
A 0% APR is the edge case: with r = 0 the formula reduces to M = P ÷ n (principal split evenly).
How each payment splits
- Interest = current balance × r
- Principal = payment − interest
- New balance = balance − principal
Interest is charged on the remaining balance, which is largest at the start — that’s why early payments are mostly interest. Payments are applied fees first, then accrued interest, then principal.
$30,000 at 7.5% APR over 72 months
The first payment is mostly interest; the last is almost all principal. (Exact figures, simple interest.)
| Payment | Amount | Interest | Principal |
|---|---|---|---|
| #1 | $518.70 | $187.50 | $331.20 |
| #2 | $518.70 | $185.43 | $333.27 |
| … | … | … | … |
| #72 (final) | $518.70 | ≈ $3.22 | ≈ $515.48 |
| Totals | $37,346.64 paid | $7,346.64 interest | |
The first payment is ~36% interest; the last is under 1%. That’s the whole story of amortization in two rows.
Simple interest vs. precomputed interest
It decides whether paying early actually saves a buyer money.
Simple interest (common)
Interest accrues on your actual outstanding balance, daily or monthly. Paying extra or early reduces the balance and the total interest. This is the more common method, and the one a buyer who may pay off early wants.
Precomputed interest (uncommon)
All the interest is calculated up front, added to principal, and split across payments. Extra payments don’t cut owed interest the same way; an early payoff may yield only a partial “unearned interest” rebate.
Watch for the Rule of 78s
APR, extra payments, term length & balloons
The concepts every dealer should be able to explain at the desk.
APR vs. interest rate — compare like with like
Extra principal payments
On a simple-interest loan, extra money applied to principal lowers the balance future interest accrues on — cutting total interest and shortening the term. Confirm there’s no prepayment penalty and that the servicer applies it to principal, not future installments.
Term length tradeoff
A longer term lowers the monthly payment but raises total interest — and keeps the borrower upside down longer. As of early 2026 the average new-car loan ran ~69 months, with over a third of loans past six years.
Negative equity (“upside down”)
Owing more than the car is worth. Because principal pays down slowly early while cars depreciate fast, buyers can be upside down for much of a long loan. Rolling that balance into the next loan makes it more expensive.
Balloon payment
A large one-time payment at the end (generally more than 2× the regular payment). It lowers the monthly payments but leaves a lump sum due at maturity. A standard fully-amortizing loan instead ends at a $0 balance.
Amortization FAQ
How the schedule, payment, and interest split work.
How is the monthly payment calculated?
With the standard amortization formula: M = P · r · (1+r)ⁿ ÷ ((1+r)ⁿ − 1), where P is the amount financed, r is the periodic rate (APR ÷ 12 for monthly payments), and n is the number of payments. For $30,000 at 7.5% APR over 72 months, r = 0.00625 and n = 72, giving a payment of $518.70. A 0% APR simply splits the principal evenly across the term.
Why is so much of my early car payment going to interest?
Because interest each month is charged on the remaining balance, which is highest at the start. As the balance falls, the interest portion shrinks and more of each fixed payment goes to principal. On a $30,000 loan at 7.5% for 72 months, the first payment is $518.70 — $187.50 interest and $331.20 principal — while the final payment is about $3 interest and $515 principal.
Are most U.S. auto loans simple interest or precomputed?
Most are simple interest, where interest accrues on your actual outstanding balance (the CFPB calls this the more common method). Precomputed interest — where all the interest is calculated up front, added to principal, and split across payments — is uncommon. If a buyer expects to pay off early, confirm the contract is simple interest.
What’s the difference between the interest rate and the APR?
The interest rate (note rate) is the cost of borrowing the principal. The APR is that rate plus lender fees such as origination charges, so it’s usually higher and reflects the fuller cost. Because the Truth in Lending Act requires APR disclosure, the CFPB says to compare offers APR-to-APR — never an APR against another lender’s plain interest rate.
If I pay extra, does it lower my total interest?
On a simple-interest loan, yes — extra money applied to principal lowers the balance future interest accrues on, so you pay less interest overall and finish sooner. Check your loan documents first to confirm there’s no prepayment penalty and that the extra is applied to principal. On a precomputed loan, extra payments don’t reduce owed interest the same way.
What is the Rule of 78s?
It’s a precomputed-interest method that front-loads finance charges into the early months, so a borrower who pays off early gets a smaller interest rebate than under the standard actuarial method. Its use is limited or prohibited by various federal and state laws — dealers offering in-house financing should confirm what their state allows.
Does this include taxes and fees?
No — it amortizes the amount financed only. A real contract may roll in taxes, doc/title fees, and optional products. Use the out-the-door and payment calculators for the full picture; this is an estimate, not a financing offer.
Sources
- CFPB — What is amortization?
- CFPB — Simple vs. precomputed interest
- CFPB — Interest rate vs. APR
- CFPB — Negative equity
Estimate only — not a financing offer. The schedule amortizes the amount financed and excludes taxes, fees, and add-ons. Definitions follow CFPB guidance; market averages are 2026 industry data. This tool uses the same amortization math as the AutoDealer.io deal desk. See the dealer glossary.
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