Universal Unit Converter
Instantly convert Length, Weight, Temperature, Area, Volume, Speed, Digital Storage, and Pressure between Metric (SI) and US/Imperial units with exact NIST conversion factors.
🌐 All Length & Distance Units (Click Any Card to Copy)
Input: 10 mMetric ↔ Imperial Conversion Cheat Sheet (24 Standard Factors)
Exact international conversion ratios for length, weight, volume, area, speed, and temperature.
Most Popular Unit Conversions
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How Metric (SI) and Imperial Unit Conversions Work
Exact International Yard & Pound Agreement
Since the 1959 International Yard and Pound Agreement (adopted by NIST), 1 inch is defined as exactly 25.4 millimeters (2.54 cm), 1 foot is 0.3048 meters, and 1 pound is 0.45359237 kilograms—eliminating rounding drift across engineering and trade calculations.
Temperature Affine Transformations
Unlike length or weight, temperature scales do not share a zero point (except Kelvin and Rankine at absolute zero). To convert Celsius to Fahrenheit, multiply by 9/5 (1.8) and add 32; to convert Celsius to Kelvin, add 273.15.
Decimal (SI) vs. Binary (IEC) Data Units
Storage manufacturers define 1 Gigabyte (GB) as 1,000,000,000 bytes (10⁹), whereas operating systems often report Gibibytes (GiB = 1,024³ = 1,073,741,824 bytes). Our Digital Storage tab converts both side-by-side.
Frequently Asked Questions — Unit Converter
How do I convert centimeters (cm) to feet and inches?
Divide centimeters by 2.54 to get total inches, then divide by 12 for whole feet and keep the remainder as inches. Our Length converter automatically displays both decimal feet and the exact Feet + Inches breakdown (e.g., 180 cm = 5 ft 10.87 in).
How many pounds (lbs) are in 1 kilogram (kg)?
There are 2.20462262 pounds in 1 kilogram. Conversely, 1 pound equals exactly 0.45359237 kilograms (453.59 grams).
How do I convert Celsius to Fahrenheit quickly?
Multiply the Celsius temperature by 1.8 (or 9/5) and add 32. For example, 25°C × 1.8 + 32 = 77°F.
How many square feet are in 1 acre and 1 hectare?
One acre equals exactly 43,560 square feet (4,046.86 square meters). One hectare equals 10,000 square meters, or approximately 107,639.1 square feet (2.47105 acres).