Free online calculators, your numbers stay private
Percentages, BMI, loans and mortgages, tips, fractions, grades, compound interest, cooking measures, unit conversions: every calculator on this page runs locally, so your salary, weight or budget is never sent to a server.
One exception is disclosed clearly: the currency converter downloads a public table of daily exchange rates (the amounts you type still never leave your browser). And honest framing: results are math, not advice; loan or calorie numbers will not replace a professional when the stakes are real.
All 20 tools in this category
- BMI CalculatorCalculate your Body Mass Index instantly, no upload, no server, 100% private.
- Tip CalculatorCalculate tip amount, total bill and per-person split instantly, no upload, fully offline.
- VAT & Tax CalculatorAdd or remove VAT and sales tax instantly. All calculations stay on your device, nothing is uploaded.
- Fraction CalculatorAdd, subtract, multiply or divide fractions instantly, results auto-reduced, decimal shown. 100% offline, no upload.
- Percentage calculatorWork out X% of Y, what percent X is of Y, percentage change, and increase/decrease by %. No upload.
- Cooking converterConvert cooking units, cups, grams, ml, oz, by ingredient, plus °F ↔ °C. No upload.
- Unit converterConvert length, mass, temperature, volume, area, speed, data and time units. No upload.
- Currency converterConvert between 200+ currencies with daily rates, amounts stay in your browser. No upload.
- Scientific calculatorEvaluate expressions with functions, powers and constants, sin, cos, log, √, π. No upload.
- Tournament calculatorSwiss rounds, top cut, invite spots and where you stand on tiebreakers, for Magic, Pokemon, Yu-Gi-Oh and more. No upload.
- GPA CalculatorCalculate your Grade Point Average instantly, weighted by credits, fully offline. Your data never leaves your device.
- Grade CalculatorCalculate your weighted average grade and find out what score you need on your final exam.
- Running Pace CalculatorCalculate your running pace, time or distance instantly in your browser - no upload, 100% private.
- Loan CalculatorCalculate monthly payments, total cost and interest for any fixed-rate loan. 100% offline, no data leaves your device.
- Compound & Simple Interest CalculatorCalculate compound or simple interest on any investment or loan, fully offline, nothing leaves your device.
- Random Number GeneratorGenerate random integers in any range, secure, offline, and private.
- Random PickerDraw random winners from a list of names using secure randomness, with or without replacement. Nothing leaves your browser.
- Calorie CalculatorCalculate your BMR and TDEE to find daily calorie needs for weight loss, maintenance, or gain, 100% private, no upload.
- Mortgage CalculatorEstimate your monthly mortgage payment (principal, interest, tax, insurance, PMI), 100% private, no upload.
- Body Fat & Ideal Weight CalculatorEstimate your body fat percentage and ideal weight instantly, US Navy method, 100% offline, no data leaves your device.
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Frequently asked questions
Are the amounts I enter sent anywhere?
No. Calculations run in your browser, so salaries, loan amounts and body measurements stay on your device. The currency converter only downloads public exchange rates; your amounts are never transmitted.
Are the currency rates real-time?
No, and we say so on the tool: rates come from a public daily table, refreshed once a day and cached for offline use. Fine for planning, not for trading.
Can I rely on these results for financial or health decisions?
Use them as solid estimates: the formulas are standard and unit-tested. But a mortgage or a calorie target involves factors no calculator sees, so check important decisions with a professional.