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Unit Converter

Convert Length, Weight, Temperature, and Volume.

Conversion Setup

Enter the value and select the units.

Converted Result
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Calculation Breakdown:

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Conversion Details
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About this topic

Length Conversions Convert between metric and imperial distance units.

Length measures the distance between two points. The metric system uses base-10 prefixes (milli, centi, kilo), while the imperial system uses historical ratios (inches, feet, miles).

Key formulas & rules

  • •Base unit: Meter (m)
  • •1 inch = 0.0254 meters exactly
  • •1 foot = 12 inches
  • •1 mile = 5280 feet
  • •Metric uses powers of 10
  • •Imperial requires specific factors

Examples

Input Output Note
1 m 100 cm Metric shift
1 km 0.621 mi Metric to Imperial
1 ft 0.3048 m Exact factor
1 mi 1.609 km Road distance

Real-world uses

Travel distance Construction Fabric measurement
Weight & Mass Convert between metric mass and imperial weight.

In everyday usage, 'weight' often means mass. The metric system measures in grams and kilograms, while the imperial system uses ounces and pounds.

Key formulas & rules

  • •Base unit: Kilogram (kg)
  • •1 pound = 0.45359237 kg exactly
  • •1 ounce = 28.349 grams
  • •1 kilogram = 1000 grams
  • •Metric tonne = 1000 kg
  • •US ton = 2000 lbs

Examples

Input Output Note
1 kg 1000 g Metric shift
1 lb 16 oz Imperial breakdown
1 lb 0.4536 kg Imperial to Metric
1 oz 28.35 g Small mass

Real-world uses

Cooking Shipping Body weight
Temperature Convert between Celsius, Fahrenheit, and Kelvin.

Unlike length or weight, temperature scales have different zero points. Converting between them requires both a multiplier and an offset.

Key formulas & rules

  • •Celsius: Water freezes at 0°, boils at 100°
  • •Fahrenheit: Water freezes at 32°, boils at 212°
  • •Kelvin: Absolute zero is 0K (-273.15°C)
  • •°F = (°C × 9/5) + 32
  • •K = °C + 273.15
  • •°F and °C intersect at -40°

Examples

Input Output Note
0°C 32°F Freezing point
100°C 212°F Boiling point
0K -273.15°C Absolute zero
-40°C -40°F Intersection

Real-world uses

Weather Oven settings Scientific experiments
Volume & Capacity Convert between liquid and dry volume units.

Volume measures three-dimensional space. The metric system uses liters, while the US customary system uses gallons, quarts, cups, and fluid ounces.

Key formulas & rules

  • •Base unit: Liter (L)
  • •1 US gallon = 3.785 liters
  • •1 US quart = 0.946 liters
  • •1 US cup = 236.5 milliliters
  • •1 mL = 1 cubic centimeter (cc)
  • •US and UK gallons differ by ~20%

Examples

Input Output Note
1 L 1000 mL Metric shift
1 gal 4 qt US customary
1 gal 3.785 L US to Metric
1 cup 8 fl oz Cooking

Real-world uses

Cooking Fuel capacity Chemistry

Modes & formulas

1

Length

• Convert between meters, kilometers, centimeters, millimeters, inches, feet, yards, and miles. • All conversions use meters as the base unit. • Multiply by the source factor and divide by the target factor.
value × factor_source / factor_target

Every length unit has a defined ratio to the meter. For example, 1 inch = 0.0254 m, 1 foot = 0.3048 m, and 1 mile = 1609.344 m.

2

Weight

• Convert between kilograms, grams, milligrams, pounds, and ounces. • All conversions use kilograms as the base unit. • Multiply by the source factor and divide by the target factor.
value × factor_source / factor_target

1 pound = 0.45359237 kg and 1 ounce = 0.02834952 kg. These are exact by international agreement.

3

Temperature

• Convert between Celsius, Fahrenheit, and Kelvin. • Temperature uses offset formulas, not simple multiplication. • The tool first converts to Celsius, then to the target unit.
°F = (°C × 9/5) + 32 | K = °C + 273.15

Celsius is the intermediate unit. Unlike length or weight, temperature scales have different zero points, so a conversion factor alone isn't enough.

4

Volume

• Convert between liters, milliliters, gallons, quarts, cups, and fluid ounces. • All conversions use liters as the base unit. • US customary units are used (not UK imperial).
value × factor_source / factor_target

1 US gallon = 3.785411784 L, 1 quart = 0.946352946 L, and 1 cup = 0.2365882365 L. UK gallons are about 20% larger.

How to use it

Select a category tab, enter a value, and choose the From and To units. The converted result appears instantly.

Frequently asked questions

What is the difference between US and UK gallons?
1 US gallon = 3.785 L, while 1 UK gallon = 4.546 L. The tool uses US gallons.
Why does temperature need special formulas?
Because temperature scales have different zero points (0°C = 32°F). Simple multiplication won't work; you also need to add an offset.
What is the difference between the metric and imperial systems?
The metric system (used globally) is based on powers of 10 (meters, grams, liters). The imperial system (used mainly in the US) uses historical ratios (inches, pounds, gallons).
Why does temperature need a special formula?
Because temperature scales have different zero points (0°C is freezing, 32°F is freezing). You must multiply by the scale factor AND add an offset.
What is the difference between mass and weight?
Mass is the amount of matter (measured in kg). Weight is the force of gravity on that mass (measured in Newtons). In everyday use, "weight" usually means mass.
How many ounces are in a pound?
There are exactly 16 ounces in 1 pound.

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Read the full Unit Converter guide — examples & 18 FAQs