Conversion Formulas

Master unit conversions with these essential formulas. Understanding the math behind conversions helps you verify calculations and work without a calculator when needed.

Length Conversion Formulas

Metric to Imperial

  • Meters → Feet: feet = meters × 3.28084
  • Meters → Inches: inches = meters × 39.3701
  • Kilometers → Miles: miles = km × 0.621371
  • Centimeters → Inches: inches = cm × 0.393701

Imperial to Metric

  • Feet → Meters: meters = feet × 0.3048
  • Inches → Centimeters: cm = inches × 2.54
  • Miles → Kilometers: km = miles × 1.60934
  • Yards → Meters: meters = yards × 0.9144

Weight Conversion Formulas

Metric to Imperial

  • Kilograms → Pounds: pounds = kg × 2.20462
  • Grams → Ounces: ounces = grams × 0.035274
  • Metric Tons → US Tons: US tons = metric tons × 1.10231

Imperial to Metric

  • Pounds → Kilograms: kg = pounds × 0.453592
  • Ounces → Grams: grams = ounces × 28.3495
  • US Tons → Metric Tons: metric tons = US tons × 0.907185

Temperature Conversion Formulas

Temperature Scale Conversions

Celsius → Fahrenheit °F = (°C × 9/5) + 32 °F = (°C × 1.8) + 32
Fahrenheit → Celsius °C = (°F - 32) × 5/9 °C = (°F - 32) / 1.8
Celsius → Kelvin K = °C + 273.15
Kelvin → Celsius °C = K - 273.15
Fahrenheit → Kelvin K = (°F - 32) × 5/9 + 273.15
Kelvin → Fahrenheit °F = (K - 273.15) × 9/5 + 32

Volume Conversion Formulas

Metric to US Customary

  • Liters → US Gallons: gallons = liters × 0.264172
  • Liters → US Cups: cups = liters × 4.22675
  • Milliliters → Fluid Oz: fl oz = mL × 0.033814
  • Liters → US Quarts: quarts = liters × 1.05669

US Customary to Metric

  • US Gallons → Liters: liters = gallons × 3.78541
  • US Cups → Milliliters: mL = cups × 236.588
  • Fluid Oz → Milliliters: mL = fl oz × 29.5735
  • US Quarts → Liters: liters = quarts × 0.946353

Note: US gallons (3.785 L) differ from Imperial gallons (4.546 L). These formulas use US customary units.

Area Conversion Formulas

Common Conversions

  • Sq Meters → Sq Feet: sq ft = m² × 10.7639
  • Sq Feet → Sq Meters: m² = sq ft × 0.092903
  • Acres → Hectares: hectares = acres × 0.404686
  • Hectares → Acres: acres = hectares × 2.47105

Land Measurements

  • Acres → Sq Meters: m² = acres × 4046.86
  • Sq Km → Sq Miles: sq mi = km² × 0.386102
  • Sq Miles → Sq Km: km² = sq mi × 2.58999
  • Hectares → Sq Meters: m² = hectares × 10,000

Time Conversion Formulas

Time Unit Conversions

  • Hours → Minutes: minutes = hours × 60
  • Minutes → Seconds: seconds = minutes × 60
  • Hours → Seconds: seconds = hours × 3600
  • Days → Hours: hours = days × 24
  • Weeks → Days: days = weeks × 7
  • Years → Days: days = years × 365.25 (avg)
  • Years → Weeks: weeks = years × 52.1775 (avg)
  • Months → Days: days = months × 30.4375 (avg)

Quick Conversion Tips

Approximate Mental Math

  • Kilometers to miles: divide by 1.6 (or multiply by 0.6)
  • Kilograms to pounds: multiply by 2.2
  • Celsius to Fahrenheit: double it and add 30 (rough estimate)
  • Liters to quarts: they're nearly equal (1 L ≈ 1.06 qt)

Common Reference Points

  • 1 inch = 2.54 cm (exact)
  • 1 mile = 1.609 km
  • 1 kg = 2.2 pounds
  • Water freezes: 0°C = 32°F
  • Water boils: 100°C = 212°F

Need to Convert Now?

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