Convert Any Unit Instantly

The fastest free online unit converter. Choose a category, enter a value, and get instant results — 10 categories, 100+ units.

Quick Reference

Supported Conversions

Convert between 100+ units across 10 categories — all for free.

km → mi
m → ft
cm → in
kg → lb
g → oz
°C → °F
°F → °C
K → °C
km² → mi²
ha → acre
L → gal
mL → fl oz
km/h → mph
m/s → km/h
hr → min
day → hr
GB → MB
TB → GB
bar → psi
atm → Pa
kJ → kcal
kWh → J
mi → km
ft → m
lb → kg
gal → L

Why Choose Our Unit Converter?

Everything you need to convert units — fast, accurate, and free.

kg INPUT mi / ft °F / K lb / oz

Real-Time Results

Results update as you type. No submit button required — just enter a value and see the conversion instantly, including a quick reference table.

10 Categories

Length, weight, temperature, area, volume, speed, time, digital storage, pressure and energy. Over 100 units across all categories.

100% Accurate

Conversion factors sourced from NIST and SI standards. Precision up to 8 significant digits for scientific and engineering use.

Swap & Compare

One-click swap button to reverse the conversion direction. Quick reference grid shows common values at a glance.

Works Offline

All conversion logic runs in your browser with zero dependencies. No server requests, no internet required after the page loads.

Mobile Friendly

Fully responsive design that works on any device. Numeric keyboard on mobile for fast input. Clean, accessible interface.