Tools & Data
Math, unit conversions, dates and time — the core tools and data calculators.
Math23
Percentage Calculator
Percentages, discounts, increases and reverse percentages, solved instantly.
Fraction Calculator
Add, subtract, multiply and divide fractions with fully simplified results.
Random Number Generator
Random numbers by range or list, with or without repeats.
3D Dice Roller
Roll d4 to d100 as real 3D polyhedra that tumble and settle, with three visual styles.
Password Generator
Strong random passwords in your browser, adjustable length and types.
Grade Calculator
Average, weighted average, or the score you need on the final.
Unit Converter
Convert length, weight, temperature and volume, metric and imperial — with a live chart.
Statistics Calculator
Mean, median, mode, range and standard deviation of a list.
Slope Calculator
Slope, line equation, angle and distance between two points.
Density Calculator
Solve density, mass or volume from the density formula.
Speed, Distance & Time Calculator
Find speed, distance or time from the other two, with km/h and mph.
Circle Area Calculator
Area, circumference and diameter from any one measurement.
Length Converter
Convert length between meters, kilometers, miles, feet, inches and more.
Weight Converter
Convert weight between kilograms, grams, pounds, ounces and more.
Temperature Converter
Convert temperature between Celsius, Fahrenheit and Kelvin.
Volume Converter
Convert volume between liters, gallons, cups, tablespoons and more.
Speed Converter
Convert speed between km/h, mph, m/s, knots and more.
Time Converter
Convert time between seconds, minutes, hours, days and years.
Data Storage Converter
Convert data between KB, MB, GB, TB and binary units.
Energy Converter
Convert energy between joules, calories, kWh, BTU and more.
Strong Password Generator
Cryptographically strong passwords with a live entropy meter and rank levels.
Time Zone Converter
The equivalent local time between two cities, with daylight saving handled for you.
Screen Size Comparison
Compare two screens by real surface area, not just diagonal inches, with a scaled visual.