Unit Converter

Convert between metric and imperial units for length, weight, temperature, speed, area, volume, and digital storage.

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📏 Length Converter

About Unit Conversion

Unit conversion is the process of expressing a measurement in a different unit while preserving the same quantity. The need for conversion arises because different countries, industries, and scientific disciplines use different measurement systems. The two primary systems in use today are the International System of Units (SI/metric), used by most of the world, and the Imperial/US customary system, primarily used in the United States, Liberia, and Myanmar.

The metric system is based on powers of 10, making conversions between units straightforward — there are 1,000 meters in a kilometer, 1,000 grams in a kilogram, and 1,000 milliliters in a liter. The Imperial system uses less consistent conversion factors — there are 12 inches in a foot, 3 feet in a yard, 5,280 feet in a mile, 16 ounces in a pound, and so on. This inconsistency is why metric is preferred in science, engineering, and international commerce.

Temperature Conversion

Temperature conversion is unique because it involves both multiplication and addition, not just a simple ratio. The three major temperature scales — Celsius, Fahrenheit, and Kelvin — have different zero points and different degree sizes. The formula to convert Celsius to Fahrenheit is F = C × 9/5 + 32. To convert Fahrenheit to Celsius: C = (F - 32) × 5/9. Kelvin is the SI unit for temperature and simply offsets Celsius by 273.15 (K = C + 273.15). Kelvin has no negative values, as 0K represents absolute zero — the lowest theoretically possible temperature.

Digital Storage Units

Digital storage uses binary prefixes based on powers of 2 and decimal prefixes based on powers of 10, which can cause confusion. In the binary system, 1 KiB (kibibyte) equals 1,024 bytes, while in the decimal system, 1 KB (kilobyte) equals 1,000 bytes. Operating systems and storage manufacturers sometimes use different conventions, which is why a "500 GB" hard drive may show slightly less capacity in your operating system. This converter uses the standard decimal definitions (1 KB = 1,000 bytes).

Frequently Asked Questions

Why does the US still use Imperial units?
The US attempted metrication in the 1970s but it remained voluntary and never fully took hold in everyday life. While science, medicine, and the military use metric, daily measurements like road distances (miles), body weight (pounds), and cooking (cups, tablespoons) remain in Imperial/US customary units due to cultural inertia.
What is the difference between a metric ton and a US ton?
A metric ton (tonne) equals 1,000 kilograms (2,204.6 pounds). A US short ton equals 2,000 pounds (907.2 kg). A British long ton equals 2,240 pounds (1,016 kg). The metric ton is the internationally standardized unit.
How accurate are the conversions?
This tool uses precise mathematical conversion factors and JavaScript's double-precision floating-point arithmetic. Results are accurate to at least 10 significant digits, which is more than sufficient for virtually all practical applications.
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