Free Online Converter Tools

PX to REM Converter

Convert pixel values to REM units (and back) with a configurable root font size.

Color Converter

Enter a HEX color and instantly get the RGB, HSL, and component values side by side.

Length Converter

Convert between mm, cm, m, km, inches, feet, yards, and miles — all values shown at once.

Weight Converter

Convert between mg, g, kg, metric tons, oz, lb, and stone — all values shown at once.

Temperature Converter

Convert between Celsius, Fahrenheit, and Kelvin — all three values shown simultaneously.

Currency Converter

Convert between 160+ currencies using live exchange rates from exchangerate-api.com.

Time Zone Converter

Convert a date and time across 30 time zones simultaneously — add or remove zones freely.

Number to Words Converter

Convert any whole number up to 999 billion into English words instantly.

Words to Number Converter

Convert English number words like 'two million five hundred thousand' back to digits.

Number Base Converter

Convert numbers between decimal, binary, hexadecimal, and octal — all four shown at once.

Percentage Calculator

Three percentage calculators in one: A% of B, X is what % of Y, and % change from P to Q.

Age Calculator

Calculate exact age in years, months, days, total days, and total weeks from any date of birth.

Date Difference Calculator

Calculate the difference between two dates in days, weeks, months, years, hours, and minutes.

BMI Calculator

Calculate Body Mass Index in metric (kg/cm) or imperial (lb/ft/in) — shows category and reference chart.

Calculator

A clean browser calculator with +, -, —, —, %, v, x—, 1/x, and sign toggle.

CSS Unit Converter

Convert between px, rem, em, pt, vh, vw, and % simultaneously with configurable base font size and viewport dimensions.

Timestamp Converter

Convert Unix timestamps to human-readable dates and back — display multiple timezones simultaneously.

Data Storage Unit Converter

Convert bytes, KB, MB, GB, TB, PB — shows both binary (1024) and decimal (1000) interpretations.

Speed / Velocity Unit Converter

Convert between mph, km/h, m/s, knots, and ft/s — all values shown simultaneously.

Area Unit Converter

Convert between sq ft, sq m, acres, hectares, sq km, sq miles, sq in, and sq yd.

Volume Unit Converter

Convert between liters, gallons, ml, cubic meters, fluid oz, cups, pints, and more.

Pressure Unit Converter

Convert between PSI, bar, pascal, atm, torr, inHg, and more — all values shown at once.

Energy Unit Converter

Convert between joules, calories, kWh, BTU, electronvolts, and foot-pounds.

Fuel Economy Converter

Convert between MPG (US), MPG (UK/Imperial), and L/100km — with US/UK gallon distinction.

Cooking Measurement Converter

Convert cups, tablespoons, teaspoons, ml, fl oz — plus grams to volume for common ingredients.

Roman Numeral Converter

Convert integers (1—3999) to Roman numerals and Roman numerals back to integers.