Unit Converter
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How to use
- 1 Choose the category: length, weight, temperature, volume, area, or speed.
- 2 Pick the From unit and the To unit from the dropdowns.
- 3 Type a value in the input box — conversion runs automatically as you type.
- 4 Click the swap button to flip From and To and convert the result back.
- 5 For temperature, the converter uses the standard formulas: F = C × 9/5 + 32 and K = C + 273.15 — no shortcuts.
About Unit Converter
FAQ
Q How do I convert kilograms to pounds?
Multiply kg by 2.20462. So 70 kg = 70 × 2.20462 = 154.32 lb. The exact factor is 1 lb = 0.45359237 kg, so 1 kg = 2.20462262 lb. For quick estimates, double and add 10% (70 × 2.2 = 154 lb).
Q What is 5'9" in centimeters?
5 feet 9 inches = 69 inches × 2.54 = 175.26 cm. Common heights: 5'0" = 152.4 cm, 5'4" = 162.6 cm, 5'10" = 177.8 cm, 6'0" = 182.9 cm, 6'4" = 193.0 cm. Type the values in the calculator's feet and inches fields for instant conversion.
Q How do I convert Celsius to Fahrenheit?
Multiply by 9/5 (or 1.8) and add 32. So 20°C × 1.8 + 32 = 68°F. Common reference points: 0°C = 32°F (water freezes), 20°C = 68°F (room temp), 37°C = 98.6°F (body temp), 100°C = 212°F (water boils). Negative numbers work the same way.
Q Are these conversion factors exact?
Yes. Since the 1959 international yard and pound agreement, 1 inch = 0.0254 m exactly and 1 lb = 0.45359237 kg exactly. Volume conversions like 1 US gallon = 3.785411784 L are exact by definition. Displayed results are rounded to six decimal places for readability.
Q What is the difference between US and UK fluid ounces?
1 US fluid ounce = 29.5735 mL; 1 UK (imperial) fluid ounce = 28.4131 mL. This converter uses US customary units throughout. UK pints, quarts, and gallons are all about 20% larger than US — a UK pint of beer (568 mL) is noticeably bigger than a US pint (473 mL).
Q How fast is 60 mph in km/h?
60 mph × 1.609344 = 96.5604 km/h. Quick estimate: multiply by 1.6. Common speeds: 30 mph ≈ 48 km/h (US residential), 65 mph ≈ 105 km/h (US highway), 80 mph ≈ 129 km/h (Texas highway max). Speed limits posted in mph (US) and km/h (rest of world) describe different physical speeds.
Q How do I convert square feet to acres?
Divide by 43,560 (the number of square feet in an acre). A 5,000 sqft house lot is 5,000 / 43,560 = 0.115 acres. Common: 1/4 acre = 10,890 sqft, 1/2 acre = 21,780 sqft, 1 acre = 43,560 sqft. The calculator's area category handles this directly.
Q Why do my recipe results vary between Europe and the US?
Different volume units and different cup sizes. A US cup is 236.6 mL; a metric cup is 250 mL; an imperial cup is 284 mL. Recipes from outside the US assume different conversions, so weighing ingredients in grams is much more reliable than converting between cup systems.
Official resources
NIST SP 811 — Guide for the Use of the SI
Authoritative NIST publication defining exact conversion factors between SI and US customary units.
NIST — Reference on Constants, Units, and Uncertainty
Official NIST reference for SI units, prefixes, and physical constants.
BIPM — SI Brochure (9th edition)
International Bureau of Weights and Measures definition of the International System of Units.
NIST Handbook 44 — Specifications for Weighing Devices
NIST reference handbook used by US state weights-and-measures officials.