Repayment Calculator
Find how many payments you need to clear a balance from your interest rate and planned monthly repayment, with a warning when payment is too low.
Repayment Calculator Inputs
Balance still outstanding.
Results computed instantly โ your data never leaves your device.
Live Repayment Calculator Results
Real-TimeMonthly Payment
$500
46 payments to payoff
Total Interest
$2,602.47
Total Payments
$22,602.47
Starting Balance
$20,000
Repayment Schedule Snapshot
| Period | Payment | Principal | Interest | Balance |
|---|---|---|---|---|
| 1 | $500 | $391.67 | $108.33 | $19,608.33 |
| 12 | $500 | $415.65 | $84.35 | $15,157.42 |
| 24 | $500 | $443.48 | $56.52 | $9,990.52 |
| 36 | $500 | $473.18 | $26.82 | $4,477.59 |
How to Use the Repayment Calculator
- 1
Enter the current outstanding balance.
- 2
Enter the annual interest rate for the balance.
- 3
Enter the monthly payment you plan to make.
- 4
Review the estimated number of payments, total interest, total payments, and schedule snapshot.
Formula & Mathematical Basis
Variable Key
Balance_tOutstanding balance at the beginning of period t
APRAnnual percentage interest rate entered by the user
Payment_tMonthly payment, capped on the final period
Principal_tPart of the payment reducing the balance
๐ The engine stops at a zero balance or a protective 1,200-payment limit. If payment is zero or no greater than accruing interest, it returns an explicit payment-too-low status.
Step-by-Step Examples
Repaying a revolving balance
Scenario: $20,000 balance, 6.5% APR, and $500 monthly payment.
- 1.Monthly interest is the balance multiplied by 6.5% รท 1,200.
- 2.The first payment is split into interest and principal.
- 3.Each next month recalculates interest on the reduced balance.
- 4.The schedule ends with the final payment when the balance reaches zero.
Payment below interest
Scenario: $10,000 balance, 12% APR, and $50 monthly payment.
- 1.First-month interest is $10,000 ร 12% รท 1,200 = $100.
- 2.The $50 payment does not cover the $100 interest charge.
- 3.The calculator returns a warning rather than a misleading payoff date.
Practical Use Cases
- โ Estimate a payoff horizon for a known balance.
- โ Compare different monthly payment plans.
- โ Quantify interest cost over the repayment period.
- โ Identify payment plans that cannot reduce principal.
- โ Inspect the balance trend in the schedule snapshot.
Common Pitfalls
- โ Entering a monthly rate in the annual rate field.
- โ Choosing a payment that is below monthly interest.
- โ Assuming the result includes future fees, penalties, or new borrowing.
- โ Treating a fixed-rate estimate as a variable-rate forecast.
- โ Ignoring the difference between scheduled payment and final payment.
Frequently Asked Questions
What does the Repayment Calculator solve?
It estimates how many monthly payments are needed to clear a current balance when the annual rate and planned monthly payment are known.
What if my payment is too low?
If the payment does not exceed the first month interest charge, the calculator shows a warning instead of pretending the balance will be repaid.
What happens at 0% interest?
The balance is divided by the monthly payment because no interest accrues. A zero monthly payment is treated as too low when a balance remains.
Does the last payment have to equal the regular payment?
No. The final payment is capped at the remaining balance plus that period interest, so the schedule can show a smaller final payment.
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