Unit Converters — Free Online Calculators

Unit conversions come up constantly — in engineering specs, cooking recipes, scientific papers, travel planning, and everyday calculations. Getting them wrong can mean failed experiments, wasted materials, or missed deadlines. Our converters apply precise mathematical formulas so you can trust the results.

Browse 51 conversion calculators across 8 measurement categories below. Each converter includes the formula used, a pre-computed conversion table for common values, and step-by-step instructions. All calculations happen instantly in your browser.

Length (10)Weight (8)Temperature (4)Speed (5)Area (6)Volume (6)Data (6)Time (6)

Length Conversions

Kilometers to Miles

Multiply the km value by 0.621371

Miles to Kilometers

Multiply the miles value by 1.60934

Meters to Feet

Multiply the meters value by 3.28084

Feet to Meters

Multiply the feet value by 0.3048

Centimeters to Inches

Multiply the cm value by 0.393701

Inches to Centimeters

Multiply the inches value by 2.54

Yards to Meters

Multiply the yards value by 0.9144

Meters to Yards

Multiply the meters value by 1.09361

Millimeters to Inches

Multiply the mm value by 0.0393701

Inches to Millimeters

Multiply the inches value by 25.4

Weight Conversions

Kilograms to Pounds

Multiply the kg value by 2.20462

Pounds to Kilograms

Multiply the lbs value by 0.453592

Ounces to Grams

Multiply the oz value by 28.3495

Grams to Ounces

Multiply the grams value by 0.035274

Stone to Kilograms

Multiply the stone value by 6.35029

Kilograms to Stone

Multiply the kg value by 0.157473

Metric Tons to Pounds

Multiply the metric tons value by 2204.62

Pounds to Metric Tons

Multiply the lbs value by 0.000453592

Temperature Conversions

Celsius to Fahrenheit

Multiply by 9/5 and add 32 — °F = (°C × 9/5) + 32

Fahrenheit to Celsius

Subtract 32 then multiply by 5/9 — °C = (°F − 32) × 5/9

Celsius to Kelvin

Add 273.15 — K = °C + 273.15

Kelvin to Celsius

Subtract 273.15 — °C = K − 273.15

Speed Conversions

Miles per Hour to Kilometers per Hour

Multiply the mph value by 1.60934

Kilometers per Hour to Miles per Hour

Multiply the km/h value by 0.621371

Meters per Second to Kilometers per Hour

Multiply the m/s value by 3.6

Knots to Kilometers per Hour

Multiply the knots value by 1.852

Knots to Miles per Hour

Multiply the knots value by 1.15078

Area Conversions

Square Feet to Square Meters

Multiply the sq ft value by 0.092903

Square Meters to Square Feet

Multiply the sq m value by 10.7639

Acres to Hectares

Multiply the acres value by 0.404686

Hectares to Acres

Multiply the hectares value by 2.47105

Square Miles to Square Kilometers

Multiply the sq mi value by 2.58999

Square Kilometers to Square Miles

Multiply the sq km value by 0.386102

Volume Conversions

Liters to Gallons (US)

Multiply the liters value by 0.264172

Gallons (US) to Liters

Multiply the gallons value by 3.78541

Milliliters to Fluid Ounces

Multiply the ml value by 0.033814

Fluid Ounces to Milliliters

Multiply the fl oz value by 29.5735

Cups to Milliliters

Multiply the cups value by 236.588

Milliliters to Cups

Multiply the ml value by 0.00422675

Data Conversions

Gigabytes to Megabytes

Multiply the GB value by 1000

Megabytes to Gigabytes

Multiply the MB value by 0.001

Terabytes to Gigabytes

Multiply the TB value by 1000

Gigabytes to Terabytes

Multiply the GB value by 0.001

Kilobytes to Megabytes

Multiply the KB value by 0.001

Megabytes to Kilobytes

Multiply the MB value by 1000

Time Conversions

Hours to Minutes

Multiply the hours value by 60

Minutes to Hours

Divide the minutes value by 60

Days to Hours

Multiply the days value by 24

Weeks to Days

Multiply the weeks value by 7

Years to Days

Multiply the years value by 365.25

Seconds to Minutes

Divide the seconds value by 60

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