How to Convert Between Units: The Complete Reference Guide

Unit conversion is a fundamental skill used in cooking, science, construction, travel, and everyday life. Whether you need to convert miles to kilometers, pounds to kilograms, or Fahrenheit to Celsius, this guide gives you the formulas, conversion factors, and examples you need.

Length Conversions

The most common length conversions between metric and imperial systems:

• 1 inch = 2.54 centimeters
• 1 foot = 30.48 centimeters = 0.3048 meters
• 1 yard = 0.9144 meters
• 1 mile = 1.60934 kilometers
• 1 meter = 3.281 feet = 39.37 inches
• 1 kilometer = 0.6214 miles

Quick trick: To approximate miles to kilometers, multiply by 1.6. To go from kilometers to miles, multiply by 0.6.

Weight and Mass Conversions

• 1 ounce = 28.3495 grams
• 1 pound = 453.592 grams = 0.4536 kilograms
• 1 kilogram = 2.2046 pounds
• 1 stone = 14 pounds = 6.35 kilograms
• 1 metric ton = 1,000 kilograms = 2,204.6 pounds

Quick trick: To convert pounds to kilograms, divide by 2.2. For kilograms to pounds, multiply by 2.2.

Volume Conversions

• 1 teaspoon = 4.929 milliliters
• 1 tablespoon = 14.787 milliliters = 3 teaspoons
• 1 fluid ounce = 29.574 milliliters
• 1 cup = 236.588 milliliters = 8 fluid ounces
• 1 gallon = 3.785 liters
• 1 liter = 0.2642 gallons = 33.814 fluid ounces

Temperature Conversions

Temperature conversion requires formulas rather than simple multiplication:

• Fahrenheit to Celsius: °C = (°F − 32) × 5/9
• Celsius to Fahrenheit: °F = (°C × 9/5) + 32
• Celsius to Kelvin: K = °C + 273.15

Common reference points:

• Water freezes: 32°F = 0°C
• Water boils: 212°F = 100°C
• Normal body temperature: 98.6°F = 37°C
• Room temperature: 68°F = 20°C

Area Conversions

• 1 square foot = 0.0929 square meters
• 1 square meter = 10.764 square feet
• 1 acre = 43,560 square feet = 4,047 square meters
• 1 hectare = 10,000 square meters = 2.471 acres

Convert Any Unit Instantly

While memorizing common conversions is useful, our math calculators can help you work through unit-related calculations quickly and accurately. Bookmark this page as a quick reference whenever you need to convert between measurement systems.

Understanding unit conversions is not just an academic exercise — it is a practical skill that saves time, prevents errors, and helps you communicate measurements clearly across different systems.