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1 Meter = 0.001 Kilometer
The conversion calculator converts between units across all major measurement categories: length, weight, temperature, volume, area, speed, pressure, energy, and more. Type in a value, select your from/to units, and get the answer instantly with the conversion formula shown. Unit conversions come up constantly in cooking, travel, science, construction, and online shopping from international retailers where measurements may be in unfamiliar systems.
Common Unit Conversions
The most frequently needed conversions span length, weight, temperature, and volume. Memorizing a handful of key conversion factors — inches to centimeters, pounds to kilograms, Fahrenheit to Celsius — covers most everyday needs. For the rest, a conversion calculator handles the math instantly.
| Category | Common Conversion | Key Factor |
|---|---|---|
| Length | 1 inch = 2.54 cm; 1 mile = 1.609 km | Exact: 1 in = 2.54 cm |
| Weight/Mass | 1 lb = 0.454 kg; 1 oz = 28.35 g | 1 kg = 2.205 lb |
| Temperature | °C = (°F-32)×5/9; °F = °C×9/5+32 | Freezing: 32°F = 0°C |
| Volume | 1 US gallon = 3.785 L; 1 fl oz = 29.57 mL | 1 L = 33.8 fl oz |
| Area | 1 sq ft = 0.0929 m²; 1 acre = 43,560 sq ft | 1 hectare = 2.471 acres |
| Speed | 1 mph = 1.609 km/h; 1 m/s = 2.237 mph | 60 mph ≈ 97 km/h |
| Pressure | 1 psi = 6.895 kPa; 1 atm = 14.7 psi | 1 bar ≈ 14.5 psi |
Metric System Prefixes
The metric system uses standard prefixes to indicate multiples and subdivisions of base units (meter, gram, liter, second, watt, etc.). Because the system is decimal (base-10), converting between metric units only requires moving the decimal point. The prefix tells you the power of 10: kilo means 1,000, milli means 1/1,000. Learning these prefixes lets you navigate any metric measurement without memorizing individual conversion factors.
| Prefix | Symbol | Factor | Example |
|---|---|---|---|
| Giga- | G | 1,000,000,000 (10⁹) | 1 GB = 10⁹ bytes |
| Mega- | M | 1,000,000 (10⁶) | 1 MW = 10⁶ watts |
| Kilo- | k | 1,000 (10³) | 1 km = 1,000 m |
| Hecto- | h | 100 (10²) | 1 hPa = 100 Pa |
| Deci- | d | 0.1 (10⁻¹) | 1 dL = 0.1 L |
| Centi- | c | 0.01 (10⁻²) | 1 cm = 0.01 m |
| Milli- | m | 0.001 (10⁻³) | 1 mL = 0.001 L |
| Micro- | μ | 0.000001 (10⁻⁶) | 1 μm = 0.000001 m |
Temperature Conversion Reference Points
Temperature conversion between Fahrenheit and Celsius is one of the most commonly needed conversions for travelers between the US and the rest of the world. A few reference points to memorize: water freezes at 32°F (0°C), a comfortable room is around 68-72°F (20-22°C), human body temperature is 98.6°F (37°C), and water boils at 212°F (100°C) at sea level.
Fahrenheit to Celsius: °C = (°F - 32) × 5/9 Celsius to Fahrenheit: °F = °C × 9/5 + 32 Kelvin: K = °C + 273.15 Quick mental approximation (F to C): Subtract 30, divide by 2 (accurate within ±2°C for common temps)
20°C quick check: 20×2+30 = 70°F (actual: 68°F). Close enough for everyday use.
US vs Metric in Cooking
American recipes use cups, tablespoons, teaspoons, and fluid ounces. Most of the world uses metric (grams, milliliters). For dry ingredients, weight conversions vary by ingredient density: 1 cup of flour ≈ 125g, but 1 cup of sugar ≈ 200g. For liquids, volume conversions are consistent: 1 cup = 237 mL, 1 tablespoon = 14.8 mL, 1 teaspoon = 4.9 mL. Using a kitchen scale with metric units is more accurate than volume measurements for baking.
Frequently Asked Questions
How do I convert Fahrenheit to Celsius?⌄
Formula: °C = (°F - 32) × 5/9. Key reference points: 32°F = 0°C (water freezes), 68°F = 20°C (comfortable room temperature), 98.6°F = 37°C (body temperature), 212°F = 100°C (water boils at sea level). For a quick mental estimate, subtract 30 from the Fahrenheit temperature and divide by 2 — this is off by only a few degrees in the common everyday range of 40-100°F.
How many cups in a gallon?⌄
16 cups in one US gallon. The breakdown: 2 cups = 1 pint, 2 pints = 1 quart, 4 quarts = 1 gallon. So 4 × 2 × 2 = 16 cups per gallon. One cup = 8 fluid ounces, so 1 gallon = 128 fluid ounces. For cooking from large-batch recipes or scaling up, this hierarchy (cups-pints-quarts-gallons) is essential to know.
What is the difference between mass and weight?⌄
Mass is the amount of matter in an object, measured in kilograms or pounds-mass, and does not change with location. Weight is the gravitational force acting on that mass, measured in Newtons, and varies by gravitational field. On the Moon, your mass is identical to on Earth, but you weigh about 1/6 as much. In everyday life we use "weight" to mean mass because Earth's gravity is constant, but in physics and engineering the distinction matters.
Why does the US still use imperial units?⌄
The US is one of only three countries (with Myanmar and Liberia) that has not officially adopted the metric system as its primary measurement standard. The Metric Conversion Act of 1975 made conversion voluntary rather than mandatory. While science, medicine, military, and most manufacturing use metric, consumer products and everyday life retained customary units due to infrastructure costs of transition and public familiarity. Most US industries that export globally use metric internally while labeling products in both systems.
How do I convert square feet to square meters?⌄
Multiply square feet by 0.0929 to get square meters. Divide square meters by 0.0929 (or multiply by 10.764) to get square feet. Example: a 1,500 square foot apartment = 1,500 × 0.0929 = 139.4 square meters. Note: area units scale by the square of the linear conversion factor. Since 1 foot = 0.3048 meters, 1 square foot = 0.3048² = 0.0929 square meters.