Convert between metric, imperial, and scientific units in one place — no app to install, no sign-up, no ads interrupting your work. Just pick a category, type a number, and get an instant, accurate result with the exact formula shown alongside it.
Whether you’re cooking from a recipe in cups instead of milliliters, checking a fever in Fahrenheit instead of Celsius, converting a car’s fuel economy from mpg to km/L, or double-checking a shipping weight in kilograms versus pounds — this tool covers it.
Pick a category below, then type into either box — it converts as you type.
How to Use This Converter
Quick Conversion Reference
A few commonly searched conversions from each category, for a fast lookup without opening the tool above.
Length
- 1 km = 0.6214 miles
- 1 mile = 1.6093 km
- 1 inch = 2.54 cm
- 1 foot = 0.3048 m
Mass
- 1 kg = 2.2046 lb
- 1 lb = 0.4536 kg
- 1 oz = 28.35 g
- 1 stone = 6.35 kg
Temperature
- 0°C = 32°F = 273.15 K
- 37°C = 98.6°F (body temp)
- 100°C = 212°F (boiling)
- -40°C = -40°F
Area
- 1 acre = 4046.86 m²
- 1 hectare = 10,000 m²
- 1 sq mile = 2.59 km²
- 1 sq ft = 0.0929 m²
Volume
- 1 liter = 0.2642 US gal
- 1 US gallon = 3.7854 L
- 1 cup = 236.6 mL
- 1 tbsp = 14.79 mL
Speed
- 1 km/h = 0.6214 mph
- 1 mph = 1.6093 km/h
- 1 knot = 1.852 km/h
- 1 m/s = 3.6 km/h
Time
- 1 day = 86,400 seconds
- 1 week = 604,800 seconds
- 1 year (avg) = 365.24 days
- 1 hour = 3,600 seconds
Digital Storage
- 1 byte = 8 bits
- 1 GB = 1000 MB
- 1 GiB = 1024 MiB
- 1 TB = 1000 GB
Data Transfer Rate
- 1 Mbps = 0.125 MB/s
- 1 MB/s = 8 Mbps
- 1 Gbps = 1000 Mbps
- 1 byte/s = 8 bit/s
Energy
- 1 kcal = 4184 J
- 1 kWh = 3.6 MJ
- 1 BTU = 1055.06 J
- 1 cal = 4.184 J
Frequency
- 1 kHz = 1000 Hz
- 1 MHz = 1,000,000 Hz
- 1 GHz = 1000 MHz
- 1 rpm ≈ 0.0167 Hz
Fuel Economy
- 1 mpg (US) ≈ 0.4251 km/L
- 10 L/100km ≈ 23.5 mpg (US)
- 1 mpg (UK) ≈ 0.3540 km/L
- 1 mi/L = 1.6093 km/L
Plane Angle
- 1 radian ≈ 57.30°
- 1 turn = 360°
- 90° = 100 gradians
- 1° = 60 arcminutes
Pressure
- 1 atm = 101,325 Pa
- 1 bar = 100,000 Pa
- 1 psi ≈ 6894.76 Pa
- 1 atm ≈ 14.7 psi
Frequently Asked Questions
How accurate are these conversions?
Why does the formula show two steps for some conversions?
Can I convert in both directions?
Why is Liters/100km different from the other fuel economy units?
Is this converter free to use?
Conversion factors are based on standard SI (metric) definitions and widely used imperial/US customary equivalents. Month and year figures for Time use calendar averages (30.44 and 365.24 days respectively) since these units don’t have a fixed length.

