Unit Converters

Length, weight, temperature, area, volume, speed and more.

Convert between metric, imperial and specialist units with confidence. From everyday conversions such as feet to meters or Fahrenheit to Celsius, to storage, pressure and energy units, our converter suite is precise, fast and free to use.

Type a value, pick the units and get an exact answer instantly — with the formula shown so you always know how the conversion works.

All unit converters

Length Converter

Convert between metric and imperial lengths: mm to inches, km to miles and more.

Weight Converter

Convert kilograms, pounds, ounces, grams, stones and tons instantly.

Height Converter

Height in cm, meters or feet & inches — with the feet-inches split done for you.

Temperature Converter

Convert Celsius, Fahrenheit, Kelvin and Rankine with one click.

Area Converter

Convert square meters, square feet, acres, hectares and more.

Volume Converter

Convert liters, gallons (US & UK), cups, cubic feet, barrels and more.

Speed Converter

Convert km/h, mph, m/s, knots and ft/s — including Mach at sea level.

Time Converter

Convert seconds, minutes, hours, days, weeks, months and years instantly.

Pressure Converter

Convert bar, psi, kPa, atmospheres, mmHg and more — tire and weather ready.

Energy Converter

Convert joules, calories, kWh, BTU and more — electricity and diet friendly.

Power Converter

Convert watts, kilowatts, horsepower (metric & imperial), BTU/h and more.

Data Storage Converter

Convert bytes, KB/MB/GB/TB and KiB/MiB/GiB — decimal vs binary made clear.

Number Base Converter

Convert between binary, octal, decimal and hexadecimal in one glance.

Frequency Converter

Convert Hz, kHz, MHz, GHz, THz, rpm and BPM instantly.

Angle Converter

Convert degrees, radians, gradians, arcminutes, arcseconds and turns.

Aspect Ratio Calculator

Find the simplified aspect ratio of any width and height — and check presets.

PPI Calculator

Pixels per inch, dot pitch and total pixels from resolution and screen size.

Fuel Economy Converter

Convert between mpg and L/100km — both directions.

Shoe Size Converter

Convert foot length to EU, US men's, US women's and UK sizes.

Clothing Size Converter

Convert clothing sizes across US, EU and UK for men and women.

Ring Size Converter

Ring sizes from circumference or diameter — US, EU and UK scales.

Paper Size Chart

ISO A, B and C paper sizes — dimensions in mm and inches, A0 to A10.

DIM Weight Calculator

Volumetric weight for shipping — international, FedEx and UPS divisors.

Battery Life Calculator

Estimate runtime from battery capacity and device draw — mAh or Wh.

Ohm's Law Calculator

Calculate voltage, current, resistance or power — V = I × R.

Resistor Color Code Calculator

Decode resistor bands or find the bands for any resistance value.

Looking for something else? Browse the other free tool collections: Financial Calculators · Date & Time Tools · Developer Tools · Text Tools · File & Image Tools · Health & Fitness Calculators · Everyday Tools · Fun & Generators · Math & Statistics.