Loan calculator
By FinTools Content updated
Your loan assumptions
Estimate monthly principal and interest in US dollars using a fixed interest rate.
Payments arrive at each month end. No fees, taxes, insurance or extra payments.
Monthly amortization schedule
Each payment reduces principal after the month's rounded interest. All amounts are USD.
View 36 payments
| Month | Opening balance | Payment | Interest | Principal | Remaining balance |
|---|---|---|---|---|---|
| 1 | $10,000.00 | $304.22 | $50.00 | $254.22 | $9,745.78 |
| 2 | $9,745.78 | $304.22 | $48.73 | $255.49 | $9,490.29 |
| 3 | $9,490.29 | $304.22 | $47.45 | $256.77 | $9,233.52 |
| 4 | $9,233.52 | $304.22 | $46.17 | $258.05 | $8,975.47 |
| 5 | $8,975.47 | $304.22 | $44.88 | $259.34 | $8,716.13 |
| 6 | $8,716.13 | $304.22 | $43.58 | $260.64 | $8,455.49 |
| 7 | $8,455.49 | $304.22 | $42.28 | $261.94 | $8,193.55 |
| 8 | $8,193.55 | $304.22 | $40.97 | $263.25 | $7,930.30 |
| 9 | $7,930.30 | $304.22 | $39.65 | $264.57 | $7,665.73 |
| 10 | $7,665.73 | $304.22 | $38.33 | $265.89 | $7,399.84 |
| 11 | $7,399.84 | $304.22 | $37.00 | $267.22 | $7,132.62 |
| 12 | $7,132.62 | $304.22 | $35.66 | $268.56 | $6,864.06 |
| 13 | $6,864.06 | $304.22 | $34.32 | $269.90 | $6,594.16 |
| 14 | $6,594.16 | $304.22 | $32.97 | $271.25 | $6,322.91 |
| 15 | $6,322.91 | $304.22 | $31.61 | $272.61 | $6,050.30 |
| 16 | $6,050.30 | $304.22 | $30.25 | $273.97 | $5,776.33 |
| 17 | $5,776.33 | $304.22 | $28.88 | $275.34 | $5,500.99 |
| 18 | $5,500.99 | $304.22 | $27.50 | $276.72 | $5,224.27 |
| 19 | $5,224.27 | $304.22 | $26.12 | $278.10 | $4,946.17 |
| 20 | $4,946.17 | $304.22 | $24.73 | $279.49 | $4,666.68 |
| 21 | $4,666.68 | $304.22 | $23.33 | $280.89 | $4,385.79 |
| 22 | $4,385.79 | $304.22 | $21.93 | $282.29 | $4,103.50 |
| 23 | $4,103.50 | $304.22 | $20.52 | $283.70 | $3,819.80 |
| 24 | $3,819.80 | $304.22 | $19.10 | $285.12 | $3,534.68 |
| 25 | $3,534.68 | $304.22 | $17.67 | $286.55 | $3,248.13 |
| 26 | $3,248.13 | $304.22 | $16.24 | $287.98 | $2,960.15 |
| 27 | $2,960.15 | $304.22 | $14.80 | $289.42 | $2,670.73 |
| 28 | $2,670.73 | $304.22 | $13.35 | $290.87 | $2,379.86 |
| 29 | $2,379.86 | $304.22 | $11.90 | $292.32 | $2,087.54 |
| 30 | $2,087.54 | $304.22 | $10.44 | $293.78 | $1,793.76 |
| 31 | $1,793.76 | $304.22 | $8.97 | $295.25 | $1,498.51 |
| 32 | $1,498.51 | $304.22 | $7.49 | $296.73 | $1,201.78 |
| 33 | $1,201.78 | $304.22 | $6.01 | $298.21 | $903.57 |
| 34 | $903.57 | $304.22 | $4.52 | $299.70 | $603.87 |
| 35 | $603.87 | $304.22 | $3.02 | $301.20 | $302.67 |
| 36 | $302.67 | $304.18 | $1.51 | $302.67 | $0.00 |
| Totals | $10,951.88 | $951.88 | $10,000.00 | $0.00 | |
Includes current assumptions, totals and every monthly payment; calculated amounts use exact USD cents.
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How the loan payment is calculated
Enter a loan principal, fixed annual interest rate and target repayment term. This tool finds the smallest whole-cent monthly principal-and-interest payment that clears the balance within that term. It reports actual payoff months and a monthly amortization schedule. All payments occur at month end.
The balance is stored in cents. Each month, interest in cents is
round(balance cents × annual interest percent / 1200). The payment first covers that interest;
the rest reduces principal. The final payment is the remaining principal plus that month's interest,
and never exceeds the regular payment. The reported totals sum the individual schedule rows.
A bounded search compares whole-cent payments against the monthly schedule until it finds the minimum that pays off within the target. Monthly interest rounds to the nearest cent, with half cents rounded up under standard JavaScript number arithmetic. Binary floating-point arithmetic can affect half-cent boundaries. This educational rounding model may differ from your lender's schedule.
Why actual payoff can be earlier than the target
A whole-cent payment cannot always spread repayment across exactly the requested number of months. For $1,000 at 0% with a 600-month target, the minimum monthly payment is $1.67; it pays off in 599 months, with a $1.34 final payment. A $1 loan at 0% pays off in 100 one-cent payments even with a 600-month target. At very high rates and long terms, cent rounding can also shorten the schedule substantially. Always compare actual payoff with your target term.
Worked loan examples
For a hypothetical $10,000 loan at 6% annual interest and a 36-month target, this model gives a regular payment of $304.22. There are 35 payments of $304.22 and a final payment of $304.18 in month 36. Total interest is $951.88 and total principal and interest is $10,951.88.
At 0% interest, $12,000 over 12 months requires twelve $1,000 payments and no interest. A $100 loan at 12% over one month has a single $101 payment: $100 principal plus $1 interest. These are illustrative assumptions, not available loan offers or recommended borrowing amounts.
Interest rate, APR and costs this tool excludes
Use the annual interest rate, not a fee-inclusive annual percentage rate (APR). APR can include costs beyond interest. Principal and interest may be only part of a mortgage payment: taxes, insurance and other charges are excluded here. This tool also excludes fees, daily accrual, irregular dates, variable rates, extra payments and balloon payments. It does not provide an affordability decision or lender quote.
Use your result
Expand the schedule to inspect interest, principal and remaining balance each month. Download the full monthly schedule as CSV with your current assumptions, totals and model limitations. Save named calculations in this browser, copy a link with your assumptions, or download a result PNG. All actions are explicit; no financial account connection or live-rate service is used. Links expose their inputs to anyone who receives them. Read the privacy details.
See loan calculator help for input limits and troubleshooting. For multiple debts with known minimum payments, use the debt payoff calculator to compare avalanche and snowball strategies. Return to the calculator directory for savings and investment tools.
Sources and context
Primary references for the concepts above. The formulas and limitations on this page describe the FinTools model; these sources do not validate its results or endorse the project.