Whatever life throws at you, there’s a tool for that.
Calculate. Convert. Compare. Solve.
Tool Corner is a practical, growing collection of free tools created to help people solve everyday problems, make calculations, understand information and get things done — all in one place.
More than just tools
Tool Corner isn’t just a directory of calculators. It’s a place to figure things out. Whether you’re working out a loan repayment, converting a measurement, checking a health number or comparing two options, the aim is the same: give you a clear, reliable answer with as little friction as possible — then get out of your way.
Who we are
We’re a team of five, with five postgraduate qualifications between us.
Where our expertise applies — and where it doesn’t
We think it’s worth being direct about this.
Our engineering and computer science background applies directly to the physics simulators, engineering calculators, unit converters, developer tools, and the verification methodology behind everything on this site. Our business psychology background applies to the workplace and occupational tools.
We are not financial advisers, accountants, tax specialists, dietitians, or medical professionals. For our finance and health calculators we do not rely on our own authority. We take the formulas and figures from official sources — HMRC for UK tax and stamp duty, the NHS and WHO for health metrics — cite them on the page, and verify every worked example numerically against the live tool. Those tools are for information and education only. They are not regulated financial advice or medical advice. How we build and verify our tools sets out the process in full.
What every tool page carries
Not “where appropriate” — on every page where the item applies:
Those sources are the published originals rather than summaries of them: national standards bodies for units and definitions, government and regulator publications for tax bands, thresholds and public holidays, the named primary papers behind clinical and fitness formulas, and manufacturers’ own technical data for material coverage rates. Where the governing document is a paywalled standard we name it precisely rather than link a shop front, so you can find the clause yourself.
Money, health, engineering, construction and psychology tools additionally carry a plain-English disclaimer stating what the tool is not: not financial advice, not medical advice, not an engineering design check, not a clinical assessment, not a materials order.
How we check the maths
A worked example that disagrees with the tool sitting above it is worse than no example at all — it looks like verification while quietly being wrong. So the examples are not proofread, they are executed. An automated harness recomputes 114 worked examples from each tool’s own inputs and fails the build if a single stated figure does not match. Pages whose example genuinely cannot be recomputed — a random number generator, a UUID’s anatomy — are listed explicitly with the reason, so an empty failure list means the work was done rather than the check narrowed.
Scored questionnaires get a further check: every percentage quoted on the page must be one the scoring actually produces. A test with six questions scored nought to four can only return twenty-five distinct percentages, and an example citing any other number is fabricated by definition.
When we get it wrong
We have, and the checks above exist because of it. An ideal-weight page once rounded a height to whole inches before applying the formula and printed a figure half a kilogram off what the tool returned. A quiz carried a worked example naming four questions the quiz did not ask and a score the scale could not produce. Both had read as correct for weeks.
So the policy is specific rather than reassuring: report an error and we check the formula against its cited source. Where the tool is wrong we fix it and move the page’s last-updated date. Where the tool is right but the explanation misled you, we rewrite the explanation — that is a defect too. Report a calculation error.
What we will not claim
No page here has been reviewed by a regulated adviser, a registered clinician or a chartered engineer, and none of them says otherwise. We do not invent sources: where a tool has no formal reference, it does not get one, and where the governing document is a paywalled standard we name it rather than link a shop front. Nothing on this site is professional advice.
Your data does not leave your device
Every calculator runs entirely in your browser. Nothing you type is uploaded, logged or stored on a server — which is why you can safely paste a salary, a health measurement or draft text into any of them. The only thing that persists is your light or dark preference, kept locally. Read the full Privacy Policy for what our analytics and advertising partners do collect.
Our philosophy
Life is full of small problems and questions. Sometimes you need to calculate something. Sometimes convert something. Sometimes compare two options. And sometimes you simply need help figuring something out.
That’s the idea behind “Whatever life throws at you, there’s a tool for that.” Tool Corner brings genuinely useful tools together in one accessible place, so the answer is never more than a search away.
Our goal
We want Tool Corner to be the place you remember when you need to figure something out. The best compliment we can get is simple: “I came here for one tool, and found several others I can use.”
How to reach us
Corrections, questions and error reports: admin@toolcorner.net
If you find a number on this site you believe is wrong, tell us. We’ll check it and either fix it or explain why it stands. Every page carries the date it was last updated.
Always improving
Tool Corner is continuously reviewed and improved. Tools may be updated for accuracy, usability, clarity, better explanations, better references and a better overall experience. New tools are added regularly — and if there’s one you wish existed, tell us.