Metric to Imperial Converter
Converting Between Metric and Imperial Units
The metric system covers most of the world — every country uses it officially except the United States, Liberia, and Myanmar. The imperial system persists in the US for everyday measurements like miles, pounds, and Fahrenheit, but science, medicine, and international trade run on metric. Knowing how to move between the two is a practical skill for travel, recipes, construction, and almost any technical project.
How to Use This Calculator
Select a category (Length, Weight, Volume, or Temperature), choose a direction (Metric → Imperial or Imperial → Metric), enter your value, and select the specific unit. Hit Convert to see all equivalent values in the target unit family at once.
Key Conversion Factors
- Length: 1 meter = 3.28084 ft | 1 km = 0.62137 mi | 1 cm = 0.3937 in
- Weight: 1 kg = 2.20462 lb | 1 g = 0.03527 oz | 1 metric ton = 2,204.62 lb
- Volume: 1 L = 0.26417 gal | 1 mL = 0.03381 fl oz | 1 L = 4.22675 cups
- Temperature: °F = (°C × 9/5) + 32 | °C = (°F − 32) × 5/9
How the Temperature Formula Works
Temperature conversions are non-linear because the two scales have different zero points. Celsius: 0° = water freezes, 100° = water boils. Fahrenheit: those same points are 32° and 212°. Key references: body temperature = 37°C / 98.6°F; room temperature = 20°C / 68°F; oven (moderate) = 180°C / 350°F.
Quick Mental Conversion Tips
- Miles to km: multiply by 1.6. 60 mph ≈ 96 km/h.
- Pounds to kg: divide by 2.2. 150 lbs ≈ 68 kg.
- °C to °F (rough): double the °C and add 30. 20°C → ~70°F (actual 68°F).
- Liters to gallons: multiply by 0.264. A 2-liter bottle ≈ half a US gallon.
- Feet to meters: divide by 3.28. 6 ft ≈ 1.83 m.
Frequently Asked Questions
Why does the US still use the imperial system?
The US officially adopted the metric system in 1975 with the Metric Conversion Act, but implementation was voluntary — and largely failed to change everyday usage. Infrastructure: road signs, product labeling, consumer expectations, and manufacturing tooling were too entrenched to replace cheaply. The US uses metric in science, medicine, the military, and international trade, but imperial persists in everyday consumer life for distances, weight, and cooking temperatures.
What is a stone in weight?
A stone is 14 pounds (6.35 kg). It's used primarily in the UK and Ireland for measuring body weight. "12 stone 3" = 171 lbs or 77.6 kg. Outside the UK and Ireland, stone is rarely used — other imperial countries measure body weight in pounds only. When comparing UK and US health data or BMI charts that reference weight, confirm whether stone or pounds is being used.
Is a US gallon the same as a UK (imperial) gallon?
No — a US gallon = 3.785 liters; a UK gallon = 4.546 liters (about 20% more). A US pint = 473 mL; a UK pint = 568 mL. This matters for fuel economy comparisons: a European car achieving 50 mpg (UK) = roughly 42 mpg (US). When a recipe or spec says "1 gallon" without specifying, check the country of origin.
How do I convert a recipe from cups to milliliters?
1 US cup = 236.6 mL ≈ 240 mL for cooking. Common conversions: ¼ cup = 60 mL, ½ cup = 120 mL, 1 tablespoon = 15 mL, 1 teaspoon = 5 mL. For precision baking, use grams instead — a cup of flour varies from 120–160g depending on packing, while 120g is always exact. A kitchen scale is the most reliable tool for converting international recipes.
What are nautical miles and how do they relate to regular miles?
One nautical mile = 1.852 km = 1.151 miles. Nautical miles are based on the Earth's geometry — 1 nautical mile equals 1 minute of arc of latitude. This makes navigation calculations much cleaner at sea and in the air. Knots (nautical miles per hour) are used in aviation and maritime navigation worldwide. If someone says a ship is traveling at 20 knots, that's 23 mph or 37 km/h.