Privacy

Your numbers never leave your browser.

Mortgage IQ is a set of static files. Every calculation runs on your own device. Nothing you type, change or save on the site is sent back to a server.

What stays on your device

• Mortgage balance, rates, terms, overpayments, fees, offset and property value.
• Your view mode and any scenarios you save.
• Every forecast, chart, schedule, comparison and CSV or backup file the site generates.

How it works

• All logic lives in one script, app.js, which your browser downloads once and runs locally.
• The code contains no network calls for your data: no fetch, no XMLHttpRequest, no beacons, no web sockets.
• There is no account, no login, no database, no analytics, no advertising and no third-party scripts, fonts or images.
• The site sets no cookies.

What is saved, and where

• Auto-save. Your inputs are saved in your browser’s local storage so they are still there when you return. This is stored only on your device. Clear your site data, or use the reset option in the calculator, to remove it.
• Share links. If you create a link that includes your figures, they are encoded after the # in the address. Browsers never send that part of a web address to a server. Anyone you give the link to can read the figures, so share it with care.
• Downloads. CSV and backup files are created in your browser and saved to your device. They are not uploaded anywhere.

What the web host can see

Like any website, the host that serves the files can see that a page or file was requested, including your IP address and browser type, in its standard access logs. That is about loading the site, not about what you enter into it. The figures you type never form part of any request.

Check it yourself

1. Open your browser’s developer tools and go to the Network tab.
2. Change any input on the calculator. No new request appears.
3. Or load the page, switch your device to airplane mode, and keep using it. It carries on working.

Not financial advice

Mortgage IQ is for illustration only. Check figures with your lender or a qualified mortgage adviser.