Unit Converter

Fast, free, and instant — convert Length, Weight, Temperature, Time & Speed right in your browser. No sign-up required.

About This Unit Converter

This universal unit converter lets you instantly convert between the most commonly used measurement units across five essential categories: Length, Weight (Mass), Temperature, Time, and Speed.

All conversions happen entirely in your browser — there are no API calls, no server round-trips, and no data stored. Just select a category, pick your units, type a value, and get the result in milliseconds.

The converter uses a base-unit architecture: every unit is defined by its conversion factor to a base unit (meter for length, kilogram for weight, second for time, meter/second for speed). Temperature is handled separately using the correct non-linear formulas via Kelvin as the intermediate base.

Common Conversion Reference

📏 Length

1 km = 1,000 m
1 mile = 1.60934 km
1 foot = 30.48 cm
1 inch = 2.54 cm
1 yard = 0.9144 m

⚖️ Weight

1 kg = 2.20462 lb
1 lb = 453.592 g
1 oz = 28.3495 g
1 tonne = 1,000 kg
1 kg = 35.274 oz

🌡️ Temperature

0°C = 32°F = 273.15 K
100°C = 212°F = 373.15 K
-40°C = -40°F
37°C = 98.6°F (body temp)
Absolute zero = -273.15°C

⏱️Time & Speed

1 hour = 3,600 seconds
1 day = 86,400 seconds
1 year ≈ 31,557,600 s
1 km/h = 0.27778 m/s
1 mph = 1.60934 km/h

Frequently Asked Questions

How does the unit converter work?

Select a category, choose your From and To units, then type a value. The result appears instantly — all calculations happen in your browser with no server calls.

Which unit categories are supported?

Length (mm, cm, m, km, inch, ft, yard, mile), Weight (mg, g, kg, tonne, oz, lb), Temperature (°C, °F, K), Time (ms, s, min, h, day, week, month, year), and Speed (m/s, km/h, mph, knot, ft/s).

How is temperature conversion handled?

Temperature uses non-linear formulas. Celsius to Kelvin: K = °C + 273.15. Fahrenheit to Kelvin: K = (°F + 459.67) × 5/9. All other conversions go through Kelvin as the base unit.

Can I swap the From and To units?

Yes — click the ↕ swap button between the two fields. It swaps the units and also moves the output value into the input field so you can continue converting in the reverse direction.

Is this converter free to use?

Completely free, with no sign-up, no account, and no data stored. All conversions happen client-side in your browser.