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Popular Unit Conversions

The most-searched unit pairs, each with an instant converter, the exact formula, and a quick reference table. Every conversion uses internationally agreed exact factors and runs entirely in your browser — nothing is uploaded. For anything beyond these pairs, open the full unit converter (12 categories, 70+ units).

📏 Length

cm → in · Centimeters to Inches

1 cm = 0.3937 in · inches = cm ÷ 2.54

in → cm · Inches to Centimeters

1 in = 2.54 cm · cm = inches × 2.54

mm → in · Millimeters to Inches

1 mm = 0.0394 in · inches = mm ÷ 25.4

in → mm · Inches to Millimeters

1 in = 25.4 mm · mm = inches × 25.4

m → ft · Meters to Feet

1 m = 3.28 ft · feet = meters × 3.28084

ft → m · Feet to Meters

1 ft = 0.3048 m · meters = feet × 0.3048

km → mi · Kilometers to Miles

1 km = 0.6214 mi · miles = km ÷ 1.609344

mi → km · Miles to Kilometers

1 mi = 1.61 km · km = miles × 1.609344

⚖️ Weight

kg → lb · Kilograms to Pounds

1 kg = 2.2 lb · pounds = kg × 2.20462

lb → kg · Pounds to Kilograms

1 lb = 0.4536 kg · kg = pounds ÷ 2.20462

g → oz · Grams to Ounces

1 g = 0.0353 oz · ounces = grams ÷ 28.3495

oz → g · Ounces to Grams

1 oz = 28.35 g · grams = ounces × 28.3495

🌡️ Temperature

°C → °F · Celsius to Fahrenheit

1 °C = 33.8 °F · °F = °C × 9⁄5 + 32

°F → °C · Fahrenheit to Celsius

1 °F = -17.22 °C · °C = (°F − 32) × 5⁄9

🧪 Volume

gal → L · Gallons to Liters (US)

1 gal = 3.79 L · liters = gallons × 3.78541

L → gal · Liters to Gallons (US)

1 L = 0.2642 gal · gallons = liters ÷ 3.78541

Cooking & Baking

Weight-to-volume pairs use an ingredient density picker (22 ingredients), because a cup of flour is not a cup of honey.

g → cup · Grams to Cups

By ingredient · cups = grams ÷ (236.588 × density)

cup → g · Cups to Grams

By ingredient · grams = cups × 236.588 × density

g → tbsp · Grams to Tablespoons

By ingredient · tablespoons = grams ÷ (14.787 × density)

tbsp → g · Tablespoons to Grams

By ingredient · grams = tablespoons × 14.787 × density

g → ml · Grams to Milliliters

By ingredient · ml = grams ÷ density

ml → g · Milliliters to Grams

By ingredient · grams = ml × density

ml → cup · Milliliters to Cups (US)

cups = ml ÷ 236.588

cup → ml · Cups to Milliliters (US)

ml = cups × 236.588

fl oz → ml · Ounces to Milliliters (fl oz)

ml = fl oz × 29.5735

ml → fl oz · Milliliters to Ounces (US fl oz)

fl oz = ml ÷ 29.5735

Why exact factors matter

Since 1959 the inch has been defined as exactly 2.54 cm, the pound as exactly 0.45359237 kg, and the mile as exactly 1.609344 km. Conversions built on these definitions are exact — the only rounding happens when a result is displayed. Temperature is different: Celsius and Fahrenheit are related by an affine formula (× 9⁄5 + 32), not a pure factor, because the scales have different zero points. Each converter page shows the precise formula so you can verify or reproduce any result by hand.