Unit conversion is the process of changing a measurement from one unit to another without changing its quantity. It's essential in science, engineering, cooking, and travel.
The Core Principle
Every conversion uses a conversion factor — a ratio that expresses how many of one unit equals another. To convert, multiply by the factor that cancels the original unit and leaves the target unit.
Metric vs. Imperial
The metric system (meters, grams, liters) is based on powers of 10, making conversions simple: just move the decimal. The imperial system (feet, pounds, gallons) uses arbitrary ratios, requiring memorized factors.
Temperature Is Special
Temperature conversions aren't simple multiplications because the scales have different zero points. To convert Celsius to Fahrenheit: °F = °C × 9/5 + 32. To convert Fahrenheit to Celsius: °C = (°F − 32) × 5/9.
Common Pitfalls
- Confusing mass and weight — they're different in physics.
- Forgetting that area and volume conversions involve squared or cubed factors.
- Mixing up fluid ounces (volume) and ounces (weight).
Our conversion calculators handle all the factors for you — just pick your units and enter a value.