Free Online Unit Converter

Convert length, mass, temperature, and units across 11 more categories. Fast, accurate, and completely free.

Type a conversion like 'meters to feet' or 'celsius to fahrenheit' and press Enter

Conversion Categories

Length

Convert length and distance units — meters, feet, inches, miles, km, yards, and more.

11 units available →

Mass

Convert mass and weight units — kilograms, pounds, ounces, grams, stones, and tons.

10 units available →

Temperature

Convert temperature between Celsius, Fahrenheit, Kelvin, and Rankine.

4 units available →

Area

Convert area units — sq feet, sq meters, acres, hectares, sq miles, and more.

10 units available →

Volume

Convert volume units — liters, gallons, cups, milliliters, fluid ounces, and more.

18 units available →

Speed

Convert speed units — mph, km/h, m/s, knots, Mach, and more.

7 units available →

Data Storage

Convert digital storage units — bytes, KB, MB, GB, TB, and bits.

11 units available →

Time

Convert time units — seconds, minutes, hours, days, weeks, months, and years.

12 units available →

Pressure

Convert pressure units — PSI, bar, Pascal, atm, mmHg, and more.

10 units available →

Energy

Convert between joules, calories, kilowatt-hours, BTU, and more energy units.

14 units available →

Angle

Convert between degrees, radians, gradians, arcminutes, arcseconds, and other angle units.

7 units available →

Frequency

Convert between hertz, kilohertz, megahertz, gigahertz, RPM, and other frequency units.

8 units available →

Density

Convert between kg/m³, g/cm³, lb/ft³, lb/in³, and other density units.

11 units available →

Fuel Economy

Convert between mpg (US/Imperial), L/100km, km/L, and other fuel economy units.

6 units available →

Data Transfer Rate

Convert data transfer rate units — bps, Kbps, Mbps, Gbps, KB/s, MB/s, GB/s.

10 units available →

Popular Conversions

Open a dedicated converter page for formulas, worked examples, tables, and related conversions.

Feet to Centimeters ft to cm Inches to Centimeters in to cm Kilometers to Miles km to mi Meters to Feet m to ft Pounds to Kilograms lb to kg Ounces to Grams oz to g Kilograms to Pounds kg to lb Fahrenheit to Celsius F to C Celsius to Fahrenheit C to F Celsius to Kelvin C to K Gallons to Liters gal to l Cups to Milliliters cup to ml Liters to Gallons l to gal Miles per Hour to Kilometers per Hour mph to kph Kilometers per Hour to Miles per Hour kph to mph Square Feet to Square Meters ft2 to m2 Acres to Hectares acre to ha Megabytes to Gigabytes MB to GB Gigabytes to Terabytes GB to TB Hours to Minutes h to min Days to Hours d to h PSI to Bar psi to bar Atmospheres to Pascals atm to Pa Kilocalorie → Kilojoule kcal to kJ Kilowatt-hour → Megajoule kWh to MJ BTU → Joule BTU to J Joule → Calorie J to cal Degree → Radian deg to rad Radian → Degree rad to deg Degree → Arcminute deg to arcmin Hertz → Kilohertz Hz to kHz Megahertz → Gigahertz MHz to GHz RPM → Hertz rpm to Hz g/cm³ → kg/m³ g-cm3 to kg-m3 lb/ft³ → kg/m³ lb-ft3 to kg-m3 kg/L → kg/m³ kg-l to kg-m3 mpg(US) → L/100km mpg-us to L100km L/100km → mpg(US) L100km to mpg-us mpg → km/L mpg-us to km-l Megabits per Second to Megabytes per Second Mbps to MB-s Megabytes per Second to Megabits per Second MB-s to Mbps Gigabits per Second to Megabytes per Second Gbps to MB-s Kilobits per Second to Megabits per Second Kbps to Mbps

How to Use Our Unit Converter

Select Category

Choose from our comprehensive list of conversion categories

Enter Value

Input the value you want to convert and select your units

Get Results

Instantly see your converted value with high precision

Why Choose UnifyUnits?

Instant Results

Conversions update as you type, with no page reloads

Precise Calculations

Arbitrary-precision arithmetic, no floating-point drift

Always Free

No registration, no payment, no usage limits

Dark Mode

Easy on the eyes, day or night

All conversion factors are sourced from NIST Special Publication 811 and the BIPM SI Brochure (9th edition), and computed with arbitrary-precision arithmetic.