Why doesn't the entire world use the metric system?

The US, Liberia, and Myanmar are the only countries that haven't officially adopted the metric system. In the US, the cost and complexity of switching infrastructure, manufacturing standards, and public familiarity make full conversion challenging, though metric is used in science, medicine, and international trade.

Is a mile longer than a kilometer?

Yes, one mile equals approximately 1.609 kilometers. So a mile is about 60% longer than a kilometer. If you're running a 5K race, that's about 3.1 miles.

Why are US and UK gallons different sizes?

They diverged in 1824 when the UK standardized the imperial gallon based on a different reference. The US gallon remained based on the older English wine gallon. A UK gallon is about 20% larger than a US gallon.

How do I convert square feet to square meters?

Divide the square feet by 10.764 to get square meters. For a quick estimate, divide by 10. So 1,000 square feet is approximately 93 square meters (exactly 92.9).

What's the easiest way to remember temperature conversion?

Memorize key reference points: 0°C=32°F (freezing), 10°C=50°F, 20°C=68°F (room temp), 30°C=86°F (hot day), 37°C=98.6°F (body temp), 100°C=212°F (boiling). Then estimate from the nearest reference.

Unit Conversion: Metric to Imperial Guide

Whether you're cooking with a recipe from another country, working on an international project, or traveling abroad, unit conversion is an essential skill. The world is divided between metric and imperial systems, with many countries using a mix of both. Understanding how to convert between units quickly and accurately can save you from costly mistakes in construction, embarrassing miscalculations in the kitchen, or confusion when reading international documents. This guide covers the most important unit conversions you'll encounter.

Metric vs Imperial: understanding the two systems

The Metric System (SI) Used by most countries worldwide, the metric system is based on powers of 10, making conversions straightforward. Base units: • Length: meter (m) • Mass: kilogram (kg) • Temperature: Celsius (°C) or Kelvin (K) • Volume: liter (L) Metric prefixes: • kilo (k) = 1,000 (kilometer = 1,000 meters) • centi (c) = 0.01 (centimeter = 0.01 meters) • milli (m) = 0.001 (millimeter = 0.001 meters) The Imperial System Used primarily in the United States, with partial use in the UK and a few other countries. Common units: • Length: inch, foot, yard, mile • Mass: ounce, pound, ton • Temperature: Fahrenheit (°F) • Volume: fluid ounce, cup, pint, gallon The imperial system's relationships are less intuitive (12 inches = 1 foot, 3 feet = 1 yard, 5,280 feet = 1 mile).

Length conversions

Length is probably the most frequently converted measurement, especially in international contexts. Key conversions: • 1 inch = 2.54 cm (exact) • 1 foot = 30.48 cm • 1 yard = 0.9144 m • 1 mile = 1.609 km Quick mental estimates: • Inches to cm: multiply by 2.5 (close enough for estimates) • Feet to meters: divide by 3.3 • Miles to km: multiply by 1.6 • Km to miles: multiply by 0.6 Common use cases: • Travel distances (km vs miles) • Height (feet/inches vs cm) • Room dimensions (square feet vs square meters) • Screen sizes (always in inches, diagonally measured) Pro tip: A meter is slightly longer than a yard (about 10% longer), which helps with quick visual estimates.

Weight and mass conversions

Technically, mass (kilograms) and weight (force) are different, but in everyday use, they're interchangeable. Key conversions: • 1 ounce (oz) = 28.35 grams • 1 pound (lb) = 453.6 grams = 0.4536 kg • 1 kilogram = 2.205 pounds • 1 stone = 14 pounds = 6.35 kg (used in UK for body weight) Quick mental estimates: • Pounds to kg: divide by 2.2 (or multiply by 0.45) • Kg to pounds: multiply by 2.2 Context-specific conversions: • Cooking: grams and ounces for ingredients • Body weight: kg, pounds, or stones • Shipping: kg or pounds (watch for dimensional weight!) • Precious metals: troy ounces (31.1g, not 28.35g) Common mistake: Confusing fluid ounces (volume) with ounces (weight). They're different measurements!

Temperature conversions

Temperature conversion is essential for weather, cooking, and science. The formulas: • °C to °F: multiply by 9/5, then add 32 • °F to °C: subtract 32, then multiply by 5/9 Key reference points: • Freezing water: 0°C = 32°F • Body temperature: 37°C = 98.6°F • Boiling water: 100°C = 212°F • Room temperature: 20-22°C = 68-72°F Quick mental estimates: • Double the Celsius and add 30 (works for moderate temperatures) • Example: 20°C → 40 + 30 = 70°F (actual: 68°F) Kelvin: • Used in science • K = °C + 273.15 • Absolute zero: 0 K = -273.15°C Cooking tip: Oven temperatures in recipes often need conversion. 180°C ≈ 350°F is a common baking temperature.

Volume conversions

Volume conversions are tricky because both systems have multiple units, and some names mean different things in different countries. Metric volumes: • 1 liter = 1,000 milliliters • 1 liter = 1,000 cubic centimeters (cc) • 1 cubic meter = 1,000 liters US Imperial volumes: • 1 US gallon = 3.785 liters • 1 US quart = 0.946 liters • 1 US cup = 236.6 ml • 1 US fluid ounce = 29.57 ml UK Imperial volumes (different!): • 1 UK gallon = 4.546 liters (larger than US) • 1 UK pint = 568 ml (vs US pint = 473 ml) Cooking measurements: • 1 tablespoon (tbsp) = 15 ml • 1 teaspoon (tsp) = 5 ml • 1 cup = 240 ml (approximately) Warning: Always check whether a recipe uses US or UK measurements. A UK pint is 20% larger than a US pint!

Common conversion mistakes to avoid

Confusing similar units: • Nautical mile (1.852 km) vs statute mile (1.609 km) • Troy ounce (precious metals) vs avoirdupois ounce (regular) • US gallon vs UK gallon • US pint vs UK pint Rounding errors: • Accumulate with multiple conversions • Always convert back to check your work • Keep extra decimal places in intermediate calculations Unit mismatches: • The Mars Climate Orbiter crashed due to a metric/imperial mixup • Always double-check units in technical work • Label all values with their units Temperature vs temperature difference: • A 10°C rise is an 18°F rise • But 10°C is not 18°F! • Be clear whether you're converting a value or a difference Best practices: • Use conversion tools for precision • Know approximate conversions for quick estimates • When in doubt, ask which system is being used • Document units clearly in any technical work

Conclusion

Unit conversion is a fundamental skill that bridges the gap between different measurement systems used around the world. While the metric system's decimal-based structure makes it inherently easier to work with, understanding both systems and how to convert between them is invaluable for international work, travel, cooking, and countless other everyday situations. Remember the key reference points, practice quick mental estimates, and use our unit converter tool when precision matters. With practice, these conversions will become second nature.