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Debt Repayment Calculator — Time and Cost of Payoff

The debt repayment calculator shows how many months it will take to clear your debt at a given monthly payment and interest rate. Enter the debt amount, annual interest rate and planned monthly payment — the calculator returns the payoff time, total cost and total interest paid. Useful for budget planning, choosing a repayment strategy (snowball or avalanche) and comparing loan offers.

Reviewed byRedakcja Liczbnik
Calculator
zł
%
zł
Debt repayment resultsPayoff time (months)49
Total repayment cost (PLN)
24,500.00 PLN
Total interest paid (PLN)
4,500.00 PLN

How the calculator computes debt payoff time

Monthly interest rate = annual rate / 100 / 12 When interest rate > 0: n = ⌈−log(1 − balance × rate / payment) / log(1 + rate)⌉ When interest rate = 0: n = ⌈balance / payment⌉ If payment ≤ balance × rate (does not cover interest) → repayment impossible Total cost = payment × n Total interest = total cost − principal

Example: 20,000 PLN debt, 10% interest, 500 PLN/month payment

Monthly rate: 10%/12 ≈ 0.833%. With a 500 PLN payment on a 20,000 PLN debt: n = ⌈−log(1 − 20000×0.00833/500) / log(1.00833)⌉ ≈ 49 months. Total cost: 49 × 500 = 24,500 PLN. Total interest: 24,500 − 20,000 = 4,500 PLN.

Frequently asked questions about debt repayment

How does the debt repayment calculator work?

The calculator computes how many months it takes to pay off a debt at a given monthly payment and annual interest rate. It also shows the total repayment cost and total interest. Just enter the debt amount, interest rate and monthly payment to get instant results.

What is the snowball method?

The debt snowball method means paying off the smallest debts first, regardless of their interest rate. Each cleared debt frees up money that rolls into the next one — the snowball grows. It is psychologically motivating because you see progress quickly.

How does the avalanche differ from the snowball?

The debt avalanche method targets the highest-interest debt first. It minimises total interest paid and is mathematically optimal. It may feel slower at the start, but saves the most money over time.

What happens if my payment does not cover interest?

If the monthly payment is less than the accrued interest, the debt balance grows — this is a debt trap. The calculator flags this situation. You should increase the payment, negotiate a lower rate or seek advice from a financial counsellor.

How can I speed up debt repayment?

Key strategies include: increasing the monthly payment, making lump-sum extra payments (bonus, tax refund), consolidating debts at a lower rate and cutting unnecessary spending. Even small extra payments significantly shorten the payoff time.

Is debt consolidation worthwhile?

Consolidating multiple loans into one with a lower interest rate can reduce monthly payments and total cost. Always check fees, insurance and other charges associated with the new product. Use the calculator to compare scenarios before and after consolidation.

Indicative result

Results are indicative and based on a simplified mathematical model. They do not constitute financial or legal advice. The actual repayment schedule depends on contract terms, interest type (fixed, variable), fees and other charges. Consult a financial adviser or lending institution for details.
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