How accurate are the results?

They use standard floating-point arithmetic — the same as a spreadsheet. For money the calculators round to cents and show the exact formula used, so you can verify any result by hand.

Does the age calculator handle leap years?

Yes. It uses a month-anchored algorithm on UTC dates, so February 29 birthdays, short months and day-clamping all resolve the way a calendar would.

Can I use the loan calculator for any currency?

Yes — the math is currency-agnostic. Results display in your browser's locale format, and the tool labels every figure (principal, interest, total) so nothing is ambiguous.

Do the calculators save my inputs?

No. Inputs live only in the page. Your usage history (which tools you opened) stays on your device and can be cleared from the Dashboard at any time.

Calculators

17 tools100% Private · In-Browser

Fast, accurate everyday math — 17 smart calculators.

All calculators

Percentage CalculatorSolve every percentage problem: of, increase, decrease and more.
Age CalculatorFind your exact age in years, months and days — plus a next-birthday countdown.
BMI CalculatorCheck your Body Mass Index with metric or imperial units.
Loan EMI CalculatorCompute monthly payments, total interest and full repayment split.
Unit ConverterConvert length, weight, temperature, area, speed, data & more.
Date DifferenceCount days, weeks, months and years between any two dates.
Discount CalculatorSee final prices and exact savings for any discount percentage.
Tip CalculatorSplit bills and calculate tips per person in seconds.
Roman Numeral ConverterConvert numbers to Roman numerals and back, both directions.
Number Base ConverterConvert between binary, octal, decimal, hex and more instantly.
Aspect Ratio CalculatorSimplify dimensions to clean ratios with visual presets.
Fuel Cost CalculatorEstimate trip fuel costs and split them between passengers.
Time Zone ConverterConvert times across world cities with DST-aware precision.
Compound Interest CalcWatch investments grow: contributions, compounding and yearly charts.
Running Pace CalcSolve pace, time or distance with splits for your next race.
Savings Goal CalcSee exactly when you'll hit your savings goal, with milestones.
Invoice GeneratorNewCreate professional invoices with exact tax math, five currencies and print-to-PDF.

Files stay on your device

Processing happens in your browser — there is no upload step to trust.

No sign-up, no limits

Open a tool and use it. No account, no credits, no watermarked exports.

Explained, not magic

Every tool page documents its inputs, outputs, limits and failure modes.

About these calculators

Sixteen calculators for the math you actually do: percentages three ways, exact age in years, months and days, BMI with an honest category read-out, loan EMIs with principal-versus-interest breakdowns, unit conversion across eight categories, date differences with business days, discounts with tax, and tipping with per-person rounding.

Each calculator computes live as you type and shows its working — the formula or method is on the page, and edge cases (a zero denominator, a reversed date range, February 29 birthdays) are handled and labelled rather than hidden. Where a result is an estimate, the tool says so.

Nothing you type is submitted anywhere. The calculators are plain TypeScript running in your browser, so they keep working on a plane, in a basement, or anywhere else the signal drops.

Frequently asked questions

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