Example 1
- Balance: 3,000
- Payment: 300
- Mode: no interest
~10 months
Pure arithmetic - with interest it would take longer.
Debt repayment calculator
Type the current debt, the monthly payment, and pick No interest or With interest. At 3,000 and a 300 payment with no interest you get 10 months. At 12,000, 400, and 18% a year the calculator counts 41 months and about 4,062 of interest.
Horizon for one balance and a fixed payment. Compare with a contract: loan overpayment. Full table: amortization schedule. A sketch, not an amendment.
Results
Current debt / balance, Monthly payment, Annual interest rate (%) and Extra monthly payment (optional). The result shows up here.
How results are calculated
Debt repayment counts how many months one balance takes at a fixed payment. In No interest mode, 3,000 at 300 a month is exactly 10 months and 3,000 paid in. In With interest mode, 12,000 at 400 and 18% a year lasts 41 months, because about 4,062 of interest keeps adding to the balance. Bare 12,000 divided by 400 is 30 months: those extra 11 months are the price of 18%.
People open this calculator for a card balance or a small loan when they know the balance and a fixed payment, not a full annuity contract. Extra monthly payment 150 and a One-time extra payment of 500 at month 1, on that same 12,000, 400, and 18%, drop to 26 months and about 2,414 of interest. That is 15 months less than 41. Extra and the lump are compared with the base payment pace, without a 41-row table.
The fields are Current debt / balance and Monthly payment. The mode switch shows or hides Annual interest rate (%). Additional options hold Extra monthly payment, One-time extra payment, Apply one-time extra at month #, and Start date. Start date sets an estimated debt-free date. The calculator does not build a payment from amount and rate: you type the payment yourself.
Loan overpayment starts from remaining principal and an annuity payment from a contract. The amortization schedule builds the full table. Loan installment computes 1,112.22 from 50,000 at 12% for 5 years. Here you start from a balance and a payment you already have. Header currency only labels the amounts. A comma and a period in 18.0 mean the same rate.
The calculator waits for a positive balance and a payment that, in interest mode, must beat monthly interest. At 12,000 and 18% the month’s interest is 180, so 400 clears it and 100 would stall. This is a teaching horizon, not a credit decision.
Type 3,000 and 300, leave No interest, click Calculate, and check 10 months. Then try 12,000, 400, and 18% in With interest to see 41 months.
How to use
- Type Current debt / balance, for example 3,000, and Monthly payment, for example 300.
- Pick No interest or With interest. In the second mode type Annual interest rate (%), for example 18.
- Optionally add Extra monthly payment, a One-time extra payment and month number, and Start date.
- Click Calculate. 3,000 / 300 with no interest is 10 months. 12,000, 400, and 18% is 41 months and about 4,062 of interest.
- A compare with an annuity contract lives on loan overpayment. The full table lives on the amortization schedule.
One balance and a fixed monthly payment
Horizon for one debt and a steady payment. At 3000 and 300 with no interest you get 10 months. At 12000, 400, and 18% a year the calculator counts 41 months and about 4062 of interest.
- balance
- Current debt / balance. 3000 / 300 with no interest = 10 months. 12000 at 400 and 18% lasts 41 months, not 30.
- interest
- With interest mode charges the balance. 18% on 12000 and 400 totals about 4062, longer than 12000÷400.
- payment
- The fixed monthly amount. 300 on 3000 with no interest closes in 10 payments. +150 and +500 once shorten the 18% case.
Examples
Example 2
- Balance: 12,000
- Payment: 400
- 18% annual
Longer than 12,000÷400
Interest > 0
Part of each payment goes to interest on the balance.
Example 3
- Same as example 2
- +150/mo and +500 once
Shorter term
Less interest
Compared with payment 400 alone.
Example 4
- Current debt / balance: 3,000
- Monthly payment: 300
- Mode: no interest
~10 months
How many months to clear 3,000 at 300 per month with no interest? 10 months. 3000 ÷ 300.
When to use this calculator
- Use Debt repayment when you have one debt balance and a fixed monthly payment, and want to know when the balance reaches zero.
- This tool is useful for payoff planning, but it is not meant for designing a new loan offer.
- If you want to size the instalment for a new loan, use Loan instalment.
- If you want to analyze overpayments on an existing amortizing loan, choose Loan overpayment or Repayment schedule.
Common mistake
- A payment that is too low relative to the interest rate may fail to reduce the debt meaningfully - that is why the “never payoff / too low payment” warning matters more than the raw nominal output.
Related calculators
FAQ
How many months at 3,000 and a 300 payment with no interest?
10. 3000 / 300 = 10. Total paid 3,000, interest 0.
How long is 12,000 at 400 and 18% a year?
41 months and about 4,062 of interest. Bare 12,000 / 400 = 30, so 18% adds 11 months.
What do +150 a month and +500 once do on that 12,000?
26 months and about 2,414 of interest when the lump hits month 1. That is 15 months less than 41.
Does the calculator compute the payment from 12,000 and 18%?
No. You type Monthly payment. Here 400. An annuity from amount and rate lives on the loan installment page.
When does the rate field appear?
After you pick With interest. In No interest the field is hidden and 3,000 / 300 stays at 10 months.
How is this different from loan overpayment?
That page compares an annuity contract with extras. Here you time a horizon from a balance and a fixed payment you already know.
What if the payment is 100 on 12,000 at 18%?
Monthly interest is 180. A payment below interest never clears the balance. The calculator asks for a payment that beats interest.
Does a comma in 18.0 work?
Yes. 18,0 and 18.0 are the same rate. Header currency only labels the result.
What is Start date for?
It sets an estimated debt-free date. Without a date you see a month count, with no calendar.
Is 41 months a figure from a contract?
No. It is a sketch from the balance, the payment, and 18%. An offer may compute differently. It is not a credit decision.
Knowledge sources
The horizon is one balance and the fixed payment you type. This is a sketch, not an amendment.
Page updated in 2026.