Unit Converter – Common Physical Units
Convert between common units of length, weight, temperature, speed, and area.
About This Calculator
Convert between common units of length, weight, temperature, speed, and area. Use the calculator above for instant results.
Worked Examples
- 100 × 1/0.3048 = 328.08 feet
Answer: 328.08 feet
- 70 × 2.20462 = 154.32 lbs
Answer: 154.32 lbs
- 25 × 9/5 + 32 = 77°F
Answer: 77°F
Who Uses This Calculator?
Quick unit conversion for experiments.
Convert units for international travel.
Recipe unit conversion.
Physics and chemistry unit conversion.
Common Mistakes to Avoid
❌ Incompatible units
Cannot convert length to weight. Only convert within the same type of measurement.
❌ Precision loss
Always carry extra decimal places in multi-step calculations and round only the final answer.
Frequently Asked Questions
SI system?
International System of Units: meters, kilograms, seconds, Kelvin. Used worldwide in science. US uses customary (feet, pounds, Fahrenheit).
Common conversions to memorize?
1 inch = 2.54 cm. 1 mile = 1.609 km. 1 kg = 2.205 lb. 0°C = 32°F. 1 gallon = 3.785 L.
Why does the US use imperial?
Historical: British imperial system was used in the colonies. Metric Act of 1866 allowed metric use; a full switch was never mandated.