Free Online Unit Converter
A free unit converter converts length, weight, temperature, volume, and speed between common units instantly. Enter a value, pick a unit, and see all equivalent conversions — no signup, runs in your browser.
Convert kilometers to miles, kilograms to pounds, Celsius to Fahrenheit, liters to gallons, and km/h to mph — plus every other unit in each category. Enter a value, choose the source unit, and all equivalents update instantly. Free, no signup, calculations run locally in your browser.
Converting 1 km to all length units
- Kilometers
- 1 km
- Miles
- 0.621371 mi
- Feet
- 3,280.84 ft
- Centimeters
- 100,000 cm
Runs 100% in your browser. Your data never leaves your device.
Standard conversion factors and temperature formulas in JavaScript — all math runs locally with no server calls.
How to Use Unit Converter
- Select a unit type — length, weight, temperature, volume, or speed
- Enter the value you want to convert
- Choose the source unit from the dropdown
- All equivalent units appear instantly below
When Would You Use This?
Travelers planning road trips convert speed limits and distances between km/h and mph without guessing at mental math on the highway.
Cooks and bakers switching between metric and imperial recipes convert grams to ounces and liters to gallons in one step.
Students and engineers working across US and metric standards convert feet to centimeters or Fahrenheit to Celsius for lab reports and specs.
Frequently Asked Questions
- Is this unit converter free to use?
- Yes, completely free. No signup, no login, no payment ever.
- Do I need to create an account?
- No account needed. Open the tool and start using it immediately.
- Is my data safe?
- Everything runs in your browser. Nothing is uploaded to our servers. We cannot see your data.
- Which gallon does the volume converter use?
- Volume conversions use US liquid gallons (3.785 L). UK imperial gallons are not included.
- How accurate are the conversions?
- Conversions use standard international factors (e.g. 1 mile = 1609.344 m, 1 lb = 0.453592 kg). Results are rounded for display but use full precision internally.