About FireMathLab

Why this exists

Most retirement calculators give you a single number and no way to interrogate it. You cannot see the formula, you cannot tell which assumption is doing the heavy lifting, and you certainly cannot tell what would have to go wrong for the answer to be nonsense.

That is a strange way to treat a decision as consequential as when to stop working. FireMathLab was built on the opposite principle: every tool explains its own arithmetic, walks through a worked example, and names the conditions under which it stops being reliable. If a model ignores tax, it says so. If a projection assumes markets deliver the same return every year (which they never do), it says that too, and then offers you a thousand randomised runs and a century of market history to check the answer against.

Who builds it

FireMathLab is made by Jobi Cheriyan, operating as BrightScale Labs Limited, a small independent software company registered in England and Wales. It is not a bank, a broker, or a regulated financial adviser, and it does not employ any. It exists because he went looking for a free calculator that would show its working, could not find one, and wrote it instead.

That is a deliberate limitation, not false modesty. Everything on this site is educational: models that help you understand the shape of a decision. The decision itself is yours, and for anything significant it is worth taking to someone qualified and regulated to give advice.

What it refuses to do

• No bank connections. Nothing here asks for banking credentials or reads your transactions. You type the numbers. It takes about four minutes a month and it means there is nothing to leak.
• No selling your data. Your figures are stored against your account so you can track them over time, and they go nowhere else. They are never sold, shared, or fed to an advertiser.
• No recommendations. The tools will not tell you to buy a fund, pick a platform, or take a product. There are no affiliate links inside the calculators.
• No fake precision. A projection that says “age 54 and 3 months” is arithmetic, not prophecy. The site says so repeatedly, because a confident number is the easiest way to mislead someone.

How it stays free

The calculators are free and do not require an account. Advertising is what pays for that, and ads may appear on any page where ad policy permits it. No advertiser receives your financial figures, and nothing you enter is used to target advertising or sold to anyone. The company page sets out the funding and regulatory position in full, and the methodology page documents every engine on the site if you would rather check the numbers than take our word for any of it.

Get in touch

Corrections are genuinely welcome: if a formula here is wrong, it should be fixed. Email hello@firemathlab.com or use the contact page.