Mortgage Extra Payment Calculator

Derive financed principal from price and down payment, then compare how extra monthly principal changes interest and payoff time.

Mortgage terms

Derive the financed principal from price and down payment, then compare optional extra principal.

Property price

Results use the same monetary unit as the price you enter.

Down payment (%)

Annual interest rate (%)

Term (months)

Term unit

Extra monthly principal

Applied to principal after the regular principal-and-interest payment.

Mortgage start date

The first payment is one calendar month after this date.

Complete all valid mortgage terms to see the comparison.

Key features

Derives financed principal from the property price and down-payment percentage.
Calculates the regular fixed-rate principal-and-interest payment and projected payoff.
Compares total interest and payment count with and without extra monthly principal.
Provides an annual principal, interest, and balance schedule with extra payments applied.

Enter the property price, down-payment percentage, and annual interest rate.
Set the term, start date, and optional extra monthly principal.
Compare interest and payoff timing between the baseline and extra-payment schedules.

Compare extra-payment impact
Review differences in total interest, payment count, and payoff date with and without extra principal.
Inspect monthly balance
Read principal, interest, and remaining balance for each payment in a fixed-rate schedule.

Property and mortgage inputs are calculated only in your browser and are not transmitted or stored.

This mathematical estimate covers principal and interest only. It excludes taxes, insurance, HOA charges, PMI, fees, and country-specific rules.

How are extra principal payments applied?: The entered extra amount is added to each regular monthly payment and compared with the baseline schedule. The final payment is capped at the remaining principal plus that month's interest.
Are taxes, insurance, or prepayment fees included?: No. It uses loan principal, fixed annual rate, term, start date, and monthly extra principal only. Check actual contract costs and rules separately.