What does this debt reduction calculator show?

It estimates a regular payoff timeline and compares it with a plan that includes monthly overpayments and optional yearly one-off payments.

Why must the monthly payment exceed monthly interest?

If the payment does not exceed the interest added each month, the regular plan cannot reduce the balance.

Does it include minimum-payment rules?

No. It uses the fixed monthly payment you enter and does not model card-specific minimum-payment calculations.

Does it include fees or promotional rates?

No. Fees, balance-transfer periods, promotional rates, penalty rates, arrears, and charges are excluded.

No. It is a scenario model and does not consider regulated debt advice, affordability, credit-file effects, arrears, or lender-specific rules.

Debt planning

Debt Reduction Calculator

Model how monthly overpayments and yearly one-off payments could shorten a debt payoff timeline and reduce interest.

Use this debt reduction calculator to compare your regular repayment plan with extra monthly or yearly payments, and estimate the time and interest saved.

Inputs

Compare the current repayment plan with extra monthly or yearly payments.

Amount to pay off (£)

Monthly payment (£)

Annual Interest Rate (%)

5.0%

Yearly One-off Payment (e.g., bonus) (£)

This amount will be applied at the end of each year.

Monthly Overpayment (£)

This amount will be added to your regular monthly payment to show the impact of overpayments.

Results

See how the payoff timeline changes when overpayments are included.

Enter your repayment assumptions and calculate to compare payoff timelines.

Assumptions

What this debt payoff model assumes

These assumptions keep the payoff model transparent and separate calculator output from debt advice.

Interest rate

Fixed annual rate

The same interest rate applies every month for the full payoff model.

Monthly payment

Fixed repayment

The regular monthly payment stays constant and must exceed monthly interest.

Yearly bonus

End-of-year payment

The yearly one-off payment is applied after months 12, 24, 36, and so on.

Fees

Not included

Fees, charges, promotional rates, and penalty interest are outside this model.

Payment holidays

Not modelled

The projection assumes no missed payments, holidays, arrears, or new borrowing.

Safety cap

360 months

The calculator stops long-running scenarios after 30 years and shows a warning.

Examples

Common debt reduction scenarios

Use these examples to compare fixed payments, overpayments, and one-off lump sums.

Credit-card overpayment

A borrower adds a monthly overpayment to clear high-interest debt sooner.

The timeline shows when the overpayment plan reaches zero debt.
The interest saved card estimates the modelled interest reduction.
Actual credit-card minimum payment rules are not included.

Loan payoff acceleration

A borrower tests whether a fixed extra payment shortens a personal loan.

The regular and overpayment lines make the time saved visible.
Check lender rules before making overpayments on a fixed loan.
If interest is very low, compare the payoff plan with other money priorities.

Bonus used against debt

A user models a yearly one-off payment alongside regular monthly payments.

The bonus is applied at the end of each year in the model.
This can approximate annual bonuses, tax refunds, or planned lump sums.
The model assumes the lump sum is used consistently each year.

FAQ