Free calculators
Online CalculatorRun basic arithmetic with keyboard support, decimals, percent, clear, and backspace.
Percentage CalculatorSolve percent-of, percent-share, and percentage change questions.
Tip CalculatorCalculate tip, total, and per-person split amounts.
Unit ConverterConvert length, weight, temperature, and volume values live in your browser.
Age CalculatorCalculate age from a birth date to today or a custom reference date.
Date CalculatorAdd or subtract days, weeks, months, or years from a date.
Week Number CalculatorFind the ISO week number, ISO year, weekday, and week range for a date.
Choose the calculation you need
Each calculator focuses on one practical task and keeps the calculation in the browser. The group page connects related calculators under one subdomain.
Common calculation workflows
- Run arithmetic, percentage, and tip calculations quickly.
- Convert units for length, weight, temperature, and volume.
- Calculate age, dates, and ISO week numbers.
- Compare numeric, date, and unit answers before moving into a document, message, or spreadsheet.
Check formulas, rounding, and calendar rules
Numeric tools show the formula or conversion behind the answer where practical. Date tools distinguish calendar days, weekdays, and ISO weeks; they do not silently add public-holiday calendars or claim financial, scientific, or legal precision.