Loan amortization calculatorLoan amortization calculator: estimate payments and interest
Enter the loan amount, rate, and term. The calculator shows your payment, estimated total interest, and — under the assumptions shown — exactly what extra payments save you. Early payments are almost all interest: on a $200,000 loan at 6%, the first $1,199.10 payment contains $1,000.00 of interest and only $199.10 of principal. Extra payments attack principal directly, which is why they punch far above their weight.
Monthly payment
$1,199
$231,676 total interest over the loan
Payoff timeline
30 years
Total interest
$231,676
Year-by-year amortization schedule
| Year | Paid | Principal | Interest | Balance |
|---|---|---|---|---|
| 1 | $14,389 | $2,456 | $11,933 | $197,544 |
| 2 | $14,389 | $2,608 | $11,782 | $194,936 |
| 3 | $14,389 | $2,768 | $11,621 | $192,168 |
| 4 | $14,389 | $2,939 | $11,450 | $189,229 |
| 5 | $14,389 | $3,120 | $11,269 | $186,109 |
| 6 | $14,389 | $3,313 | $11,076 | $182,796 |
| 7 | $14,389 | $3,517 | $10,872 | $179,279 |
| 8 | $14,389 | $3,734 | $10,655 | $175,545 |
| 9 | $14,389 | $3,964 | $10,425 | $171,580 |
| 10 | $14,389 | $4,209 | $10,180 | $167,371 |
| 11 | $14,389 | $4,468 | $9,921 | $162,903 |
| 12 | $14,389 | $4,744 | $9,645 | $158,159 |
| 13 | $14,389 | $5,037 | $9,353 | $153,122 |
| 14 | $14,389 | $5,347 | $9,042 | $147,775 |
| 15 | $14,389 | $5,677 | $8,712 | $142,098 |
| 16 | $14,389 | $6,027 | $8,362 | $136,070 |
| 17 | $14,389 | $6,399 | $7,990 | $129,671 |
| 18 | $14,389 | $6,794 | $7,595 | $122,878 |
| 19 | $14,389 | $7,213 | $7,176 | $115,665 |
| 20 | $14,389 | $7,658 | $6,732 | $108,007 |
| 21 | $14,389 | $8,130 | $6,259 | $99,877 |
| 22 | $14,389 | $8,631 | $5,758 | $91,246 |
| 23 | $14,389 | $9,164 | $5,225 | $82,082 |
| 24 | $14,389 | $9,729 | $4,660 | $72,353 |
| 25 | $14,389 | $10,329 | $4,060 | $62,024 |
| 26 | $14,389 | $10,966 | $3,423 | $51,058 |
| 27 | $14,389 | $11,642 | $2,747 | $39,416 |
| 28 | $14,389 | $12,361 | $2,029 | $27,055 |
| 29 | $14,389 | $13,123 | $1,266 | $13,932 |
| 30 | $14,389 | $13,932 | $457 | $0 |
How to use
- 1
Enter your loan amount, annual rate, and term to get the standard monthly payment.
- 2
Add an "Extra payment per month" — even $50 — and watch the interest-saved figure jump.
- 3
Expand the payment schedule to see the year-by-year split of principal vs. interest.
- 4
Compare terms (e.g. 15 vs. 30 years) to see the true cost of a longer loan.
- 5
Print the schedule before negotiating — knowing your numbers is leverage.
Benefits
Principal and interest estimates
See modeled interest separately from the loan amount; fees and other costs are excluded.
Extra payments, quantified
Compare the modeled interest with and without extra principal payments.
Full schedule, no spreadsheet
An annual summary shows payments, principal, interest, and remaining balance.
Negotiate with data
Use the illustration to discuss payment assumptions with a lender.
Read the amortization estimate
The schedule applies the entered annual rate and payment frequency to the opening balance, then subtracts the scheduled payment. The split between interest and principal changes as the balance declines. The output is a mathematical schedule under the selected assumptions, not a lender payoff quote.
Extra payments
The extra-payment scenario assumes the additional amount reduces principal. The payment and payoff schedule may differ if a lender holds partial payments, uses another accrual method, changes the rate, or charges fees.
Biweekly option
The biweekly model uses 26 half-payments per year, which totals 13 monthly-equivalent payments. Actual servicers may credit payments on different dates or apply them under different terms; confirm the schedule with the lender.
Compare scenarios using the same principal, rate, and payment assumptions. The calculator does not compare the total financial effect of choosing a shorter loan term versus investing the payment difference.
How it works
- M
- Payment per period — what you owe each month (or half of it bi-weekly)
- P
- Principal — the amount borrowed
- r
- Periodic interest rate — annual rate ÷ 12 (monthly) or ÷ 26 (bi-weekly)
- n
- Total number of payments — years × 12, or × 26 bi-weekly
Monthly payment = P*r/(1-(1+r)^(-n)), where r is the nominal annual interest rate divided by 12 and n is the number of monthly payments. Biweekly mode approximates half that payment every two weeks with interest at annual rate / 26. Extra payments reduce principal. Lender rounding, daily accrual, fees, penalties, and payment posting dates can change actual savings. Use the contractual interest rate, not a fee-inclusive loan APR.
Worked example
A $200,000 loan at 6% over 30 years costs $1,199.10 a month and $231,676 in total interest. Add $200 a month and it ends in 21 years instead of 30 — saving $79,800.51 in interest.
Understanding your results
The payment and total-interest figures follow the entered principal, nominal rate, term, and payment schedule. An extra-payment scenario shortens the modeled balance schedule; lender fees, payment posting rules, and contract terms can change real results.
Sources and methodology
These resources explain related concepts. They do not certify or endorse this calculator. See the assumptions and worked example above.
- Interest rate and APR — CFPB ↗
Explains why a borrowing APR can include charges beyond the interest rate.
Frequently asked questions
Take a $200,000 loan at 6% over 30 years: the payment is $1,199.10 a month, and the total interest comes to $231,676 — more than the loan itself. The payment formula is exact; what varies is how fast you pay it down.
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Open calculatorFigures are estimates for education only — not financial advice. Results depend on the assumptions you enter. Read the full disclaimer.