Free online calculators and converters — BMI, loan payments, percentages, unit conversion, pace, and more. No sign-up. Everything runs in your browser.
QuickCalc is a free collection of everyday calculators and converters. There is no sign-up, no download, and no app to install. Open a page, enter your numbers, and get an answer.
Every calculation runs as JavaScript inside your own browser. Whatever you type — a salary, a loan balance, a body measurement — never leaves your device. Nothing is transmitted to a server and nothing is stored. Refresh the page and it is gone. That is also why no account is required.
Most calculator sites hand you a number and stop. That is fine when you already know what the number means, and unhelpful when you do not.
Each tool here includes a short write-up covering the formula it uses, the assumptions built into it, and the situations where the result will be wrong. A BMI figure means very little without knowing that BMI cannot distinguish muscle from fat. A loan payment is misleading if you do not know it excludes tax and insurance. Understanding the shape of a calculation is usually more valuable than the specific output.
Nothing here is professional advice. The health calculators use general population formulas that will not fit every individual. The financial calculators ignore tax treatment, fees, and personal circumstances. The pregnancy due date estimator is a rule of thumb, not a clinical assessment.
Where a decision matters — medical, legal, or financial — use these results as a starting point for a conversation with someone qualified, not as a substitute for one.
If a calculation looks wrong, an explanation is unclear, or a tool you need is missing, please get in touch. Reports of errors are especially welcome and are checked and fixed.