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Metric Conversion Calculator

Convert measurements seamlessly across the International System of Units (metric SI) and US Customary / British imperial standards. Our comprehensive

Conversions
Select the category and starting measurement unit.
Enter numerical quantity to convert across all equivalent units.
Formula & Methodology
Ratio Units: Converted = Value × (Factor_From ÷ Factor_To) | Temperature: °F = (°C × 9/5) + 32

For ratio dimensions (length, mass, volume), quantities are transformed to base SI standards (meters, kilograms, liters) by multiplying by the exact NIST factor, then divided by the target unit factor. Temperature conversions apply physical offsets: °C to °F uses (°C × 1.8) + 32, and Kelvin is computed as °C + 273.15.

Feet Equivalent

3.2808 ft

Overview

Convert measurements seamlessly across the International System of Units (metric SI) and US Customary / British imperial standards. Our comprehensive hub converts length, mass, fluid volume, and temperature simultaneously across all recognized units. Note that temperature follows an affine scale with zero-point offsets rather than simple multiplication.

Worked Examples

Convert 100 Centimeters to All Length Units

Input 100 cm (Length category).

  1. Convert cm to base meters: 100 × 0.01 = 1.0 m.
  2. Convert to millimeters: 1.0 ÷ 0.001 = 1,000 mm.
  3. Convert to inches: 1.0 m ÷ 0.0254 m/in = 39.3701 inches.
  4. Convert to feet: 1.0 m ÷ 0.3048 m/ft = 3.2808 feet.
  5. Convert to yards: 1.0 m ÷ 0.9144 m/yd = 1.0936 yards.
Final Answer: 1.0 m | 39.3701 in | 3.2808 ft | 1.0936 yd

Convert 100 °C (Boiling Point of Water)

Input 100 °C (Temperature category).

  1. Convert to Fahrenheit: (100 × 9/5) + 32 = 180 + 32 = 212 °F.
  2. Convert to Kelvin: 100 + 273.15 = 373.15 K.
  3. Convert to Rankine: 373.15 × 1.8 = 671.67 °R.
Final Answer: 212 °F | 373.15 K | 671.67 °R

Convert 10 Kilograms to Common Mass Units

Input 10 kg (Mass category).

  1. Convert to grams: 10 × 1,000 = 10,000 g.
  2. Convert to pounds: 10 ÷ 0.45359237 = 22.0462 lb.
  3. Convert to avoirdupois ounces: 22.0462 × 16 = 352.74 oz.
  4. Convert to troy ounces: 10 kg ÷ 0.0311034768 kg/troy_oz = 321.51 troy oz.
Final Answer: 10,000 g | 22.0462 lb | 352.74 oz | 321.51 troy oz

How to Use This Calculator

  1. Select your measurement category and input unit from the dropdown menu.
  2. Enter your numerical measurement value.
  3. Review the primary converted metric/imperial equivalent in the result box.
  4. Examine the comprehensive multi-unit breakdown table showing all equivalent units.

Reference Table

Metric UnitSymbolImperial / US EquivalentExact Conversion Factor
Millimetermm0.03937 inches1 in = 25.4 mm (exact)
Centimetercm0.39370 inches1 in = 2.54 cm (exact)
Meterm3.28084 feet1 ft = 0.3048 m (exact)
Kilometerkm0.62137 miles1 mi = 1.609344 km (exact)
Gramg0.03527 ounces1 oz = 28.349523125 g (exact)
Kilogramkg2.20462 pounds1 lb = 0.45359237 kg (exact)
LitreL0.26417 US gal1 US gal = 3.785411784 L (exact)

Frequently Asked Questions

Are metric to imperial conversions exact or rounded?
Modern international agreements define imperial units by exact metric definitions: 1 international inch is legally defined as exactly 2.54 centimeters, 1 pound is exactly 0.45359237 kilograms, and 1 nautical mile is exactly 1,852 meters.
Why cannot temperature be converted by simple multiplication?
Temperature scales are affine rather than ratio scales because their zero points do not correspond to zero thermal energy. 0 °C is the freezing point of water, not the absence of heat. Therefore, temperature conversions require both a scaling factor (9/5) and an offset (+32 for °F, +273.15 for Kelvin).
What is absolute zero?
Absolute zero is the lowest theoretically possible temperature, where thermodynamic entropy reaches its minimum and particle kinetic energy approaches zero. It corresponds to -273.15 °C, -459.67 °F, and 0 K.
What is the difference between a fluid ounce and an ounce of weight?
An avoirdupois ounce (oz) is a unit of mass equal to 28.3495 grams. A fluid ounce (fl oz) is a unit of volume equal to approximately 29.57 milliliters in the US system. One fluid ounce of water weighs approximately 1.04 ounces.
What is the difference between a US gallon and an imperial gallon?
A US liquid gallon is defined as 231 cubic inches (exactly 3.785411784 liters). An imperial British gallon is defined as exactly 4.54609 liters (approximately 20.1% larger than a US gallon).

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Reviewed & Authored by: OnlineConvers Engineering Team · Last Updated: 2026-10-07
Conversions utilize standard BIPM, NIST Handbook 44, and ISO 80000 definitions. Ratio categories convert via SI base units (meters, kilograms, liters). Temperature conversions apply exact affine transformations with absolute zero boundary validation (-273.15 °C).