Mortgage repayment calculator
See your monthly payment and the total cost over the term — and compare repayment against interest-only, with the effect of linked offset savings.
Repayment vs interest-only
On a repayment mortgage each monthly payment chips away at the capital as well as the interest, so the debt is cleared by the end of the term. On interest-only you pay only the interest, keeping monthly costs low, but the full capital is still owed at the end and must be repaid another way.
Most residential buyers choose repayment for the certainty of owning the home outright. Interest-only is more common in buy-to-let, where investors maximise monthly rental cash flow and repay the capital from the eventual sale or other assets.
Where offset helps contractors
Contractors often hold cash in the business or personally for tax. An offset mortgage links those savings to the loan so you’re charged interest only on the difference — cutting your bill without locking the money away. See offset mortgages for how this works in practice.
Repayments, answered
How is my monthly mortgage payment calculated?+
On a repayment mortgage, the payment is the amount that clears the loan over the term at the given rate, blending interest and capital. On interest-only, you pay just the interest each month and repay the capital separately at the end.
What does the offset option do?+
Linking savings to your mortgage means interest is charged only on the balance after your savings are deducted. The calculator models this by reducing the interest-bearing balance, which lowers the interest you pay while your savings stay accessible.
Why does the real payment change later?+
This calculator assumes one rate for the whole term. In practice your introductory fixed or tracker rate ends and you move to a new rate — which is why remortgaging before you hit the standard variable rate matters.