Convert between common units of length, weight, temperature, and more.
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⚙️ How It Works
A unit converter transforms measurements from one unit to another within the same physical quantity (length, weight, temperature, volume, etc.). Each conversion uses a fixed ratio or formula. For example, 1 inch = 2.54 centimeters, so multiplying inches by 2.54 gives centimeters. Temperature conversions use formulas rather than simple ratios.
Length: 1 in = 2.54 cm, 1 ft = 0.3048 m, 1 mi = 1.60934 km | Weight: 1 lb = 0.453592 kg | Temperature: °C = (°F − 32) × 5/9
Editorial Standards
Author
BetterProduct Editorial Team
Reviewed by
Checked against standard math or conversion logic and browser-side calculation behavior.
Updated
March 2026
Best used for
Quick everyday calculations and unit checks.
Languages checked
7 language editions aligned from the same source formulas.
Use Results Responsibly
Check units and formats before you calculate.
Round only at the end if precision matters.
Use official records for deadlines, utility rates, or school policies when applicable.
❓ FAQ
How do I convert Fahrenheit to Celsius?
Subtract 32 from the Fahrenheit temperature, then multiply by 5/9. Example: 98.6°F → (98.6 − 32) × 5/9 = 37°C. To go the other way: multiply Celsius by 9/5, then add 32.
What is the metric system?
The metric system (SI) is the international standard for measurement, used by most countries. It uses base units like meters (length), kilograms (mass), and liters (volume), with prefixes like kilo (×1000), centi (÷100), and milli (÷1000).
Why does the US still use imperial units?
The US is one of only three countries (with Myanmar and Liberia) that hasn't officially adopted the metric system. Historical inertia, infrastructure costs, and cultural familiarity have slowed the transition despite several attempts.
How do I convert miles to kilometers?
Multiply miles by 1.60934 to get kilometers. A quick mental approximation: multiply by 1.6. So 10 miles ≈ 16 km. To convert km to miles, multiply by 0.621371 (or divide by 1.6 approximately).