Mortgage Calculator

Welcome to the mid-term mortgage overpayment calculator. Here you will be able to see the effects of monthly overpayments and changes in interest rates for the duration of your mortgage. You should have to hand the remaining amount of money owed on your mortgage at the time of using this tool.

If you have an existing fixed-term rate, you should add the associated duration and interest rate for that term. A market interest rate should be added to illustrate what payments will look like after your fixed term ends. This is currently defaulted to 6%. If you have no fixed-term, the market rate will be used for all payment calculations.

Disclaimer: This calculator is to be used as a guide. The author shall take no responsibility for any actions taken from the data contained herein.

Remaining Mortgage Amount:

Remaining Mortgage Lifetime: Years Months

Remaining Fixed Term: Years Months

Optional: if you have a fixed term, add the duration here.

Fixed Term Interest Rate (%):

Market Interest Rate (%):

What you expect to pay when your fixed-term (if applicable) ends

If you don't have a fixed-term this value will be used by default

Monthly Overpayment Amount:

Optional: Use this number to see the effect of overpayments on your mortgage

Overpayment Starting Month:

Use this field if you are starting overpayments on a certain month of your mortgage term.

Goal:

Reduce Mortgage Lifetime: payments will stay the same and your mortgage will be paid off earlier.

Reduce Monthly Payments: payments will reduce but your mortgage term will remain the same.

Check your mortgage agreement to understand which is applicable to you.

Debt payment + interest payment = monthly payment

Payment Schedule:

The row with this colour indicates the first payment after your fixed-term ends

Only show first payment, fixed-term-end, five-yearly intervals and final payment Show currency Save mortgage terms on your machine for next time.

Month	Debt Payment	Interest Payment	Monthly Payment	Extra Payment	Remaining Balance

Your mortgage data does not leave this page.

Built by Reece Daniels, with the help of ChatGPT.

This tool is open-source. You can find the code on GitHub.