The Calculator App
Mortgage
Calculator App
The best free mortgage calculator app for UK buyers. No download. Works on iPhone and Android. Calculate monthly repayments, overpayments, Stamp Duty, and compare mortgage deals — all in one app.
All mortgage tools in the app
Mortgage Calculator
Monthly repayments on any loan amount, rate and term
Mortgage Overpayment Calculator
See how much interest you save by paying extra each month
Stamp Duty Calculator
UK SDLT for first-time buyers, movers and second homes
Weekly Mortgage Calculator
Switch to weekly payments and cut years off your mortgage
Mortgage Cost Comparison
Compare two mortgage deals side by side over the full term
Future House Value
Project what your home will be worth in 5, 10 or 20 years
What is a mortgage calculator app?
A mortgage calculator app helps you work out how much your monthly mortgage repayments will be based on the loan amount, interest rate, and term. The best mortgage calculator apps go further — showing the total interest paid over the full term, the impact of overpayments, and how different rates compare. The Calculator App does all of this, for free, with no download required.
The mortgage repayment formula
Worked example
£250,000 mortgage at 4.5% interest over 25 years:
Frequently asked questions
Is there a free mortgage calculator app?
Yes. The Calculator Page is a free mortgage calculator app that works on iPhone and Android with no download required. Open it in Safari or Chrome, add to your homescreen, and it runs like a native app.
What is the best mortgage calculator app in the UK?
The best UK mortgage calculator app is one built specifically for UK mortgages — with SDLT (Stamp Duty), overpayment modelling, and weekly vs monthly payment comparison. The Calculator App covers all of these in one free tool.
Does the mortgage calculator app work offline?
Yes. Once loaded, the mortgage calculator works without an internet connection on iOS and Android. It uses PWA caching to store the app locally on your device.
Can I calculate mortgage overpayments in the app?
Yes. The Calculator App includes a dedicated Mortgage Overpayment Calculator that shows how much interest you save and how many years you cut by making extra payments.
Does the app include Stamp Duty?
Yes. There is a full UK Stamp Duty (SDLT) calculator built into the app, covering first-time buyer relief, second homes, and the 2025 rate changes.
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