Unit Converter

The metric system (SI) is a base-10 system used by most of the world — everything scales by powers of 10 (millimetres → centimetres → metres → kilometres). The imperial system — used primarily in the United States, Myanmar, and Liberia — uses arbitrary multipliers: 12 inches in a foot, 3 feet in a yard, 5,280 feet in a mile. This inconsistency is why conversions between the two systems always require a calculator. Metric is easier for chained calculations (e.g. engineering, science); imperial persists in everyday US life (height, road distances, cooking).

Temperature conversion is not a simple multiplication — the two scales have different zero points. The exact formulas are: °F = (°C × 1.8) + 32 and °C = (°F − 32) ÷ 1.8. A few anchors worth memorising: 0°C = 32°F (water freezes), 100°C = 212°F (water boils), 37°C = 98.6°F (body temperature), and 180°C = 356°F (common baking temp). Forgetting the +32 offset is the single most common temperature conversion mistake — use the converter above to avoid it.

1 ounce = 28.3495 grams (typically rounded to 28g in recipes). US and UK cookbooks traditionally use ounces and pounds, while the rest of the world uses grams and kilograms. Grams are strictly a measure of weight/mass. This is important: a fluid ounce (volume) and a weight ounce are completely different units — 1 fluid ounce of water ≈ 29.57 mL, but 1 fluid ounce of flour weighs far less than 1 fluid ounce of honey because densities differ. When a recipe says "1 oz flour," it almost always means weight, not volume.

They are not the same — and confusing them is one of the most common unit mistakes in international trade and travel. 1 US gallon = 3.785 litres, while 1 UK (imperial) gallon = 4.546 litres — roughly 20% larger. The same gap exists for pints: a US pint is 473 mL, a UK pint is 568 mL. This matters most when comparing fuel efficiency (mpg), buying liquids in bulk, or reading older British recipes. Always check which gallon a source is using before converting.

The exact factor is: 1 mile = 1.60934 km. So to convert km/h → mph, divide by 1.609 (e.g. 100 km/h ≈ 62.1 mph). To convert mph → km/h, multiply by 1.609 (e.g. 60 mph ≈ 96.6 km/h). A quick mental shortcut: double the km/h and subtract 20% for a rough mph estimate. This conversion matters most for speed limits when driving abroad — the US, UK, and a handful of other countries still use mph, while nearly everywhere else uses km/h.

Technically, no. Mass measures the amount of matter in an object (kilograms in SI, pounds-mass in imperial) and stays constant regardless of location. Weight is the gravitational force acting on a mass, measured in Newtons (SI) or pounds-force. On the Moon, your mass is the same as on Earth — but your weight is ⅙ as much. In everyday life, "weight" and "mass" are used interchangeably and kilograms/pounds are treated the same — but in engineering, physics, and medicine, the distinction matters. 1 kg = 2.20462 lbs (as mass).

Because area is two-dimensional, you must square the linear conversion factor. Since 1 foot = 0.3048 metres, 1 square foot = 0.0929 square metres. To convert: multiply sq ft by 0.0929, or divide sq ft by 10.764. For quick estimates, dividing by 10 is accurate enough for most property browsing. A 1,000 sq ft apartment ≈ 92.9 m². This is one of the most searched real-estate conversions globally, since the US and a few other countries list properties in square feet while most markets use square metres.

1 US cup = 236.6 mL (typically rounded to 240 mL in recipes). Other handy cooking volume conversions: 1 tablespoon = 15 mL, 1 teaspoon = 5 mL, 1 fluid ounce ≈ 30 mL. One important caveat — a "cup" is not universally standardised: the US metric cup is 240 mL, the Australian tablespoon is 20 mL (vs 15 mL elsewhere). If you're following a recipe from a different country, check its origin before converting, as small differences in volume units can noticeably affect baking results.

A hectare (ha) is the standard metric unit for land area — equal to 10,000 m² (a 100m × 100m square). An acre is the imperial equivalent, equal to 4,047 m². The conversion: 1 hectare = 2.471 acres, or roughly 2.5 acres. Hectares dominate in agriculture, forestry, and real estate outside the US; acres are standard in the US and UK for land. A football pitch is about 0.7 hectares; a typical suburban lot in the US is around 0.08 hectares (about 0.2 acres).

Digital storage uses binary prefixes, not decimal — which is why your "1 TB" hard drive shows up as slightly less in your OS. In the binary (IEC) standard: 1 kibibyte (KiB) = 1,024 bytes; 1 mebibyte (MiB) = 1,024 KiB; 1 gibibyte (GiB) = 1,024 MiB. In the decimal (SI) standard used by drive manufacturers: 1 KB = 1,000 bytes; 1 MB = 1,000 KB; 1 GB = 1,000 MB. A "1 GB" file in decimal is actually 0.931 GiB in binary — hence the apparent discrepancy on your device. Our converter handles both standards so you can reconcile them.

In 1999, NASA's Mars Climate Orbiter was lost because one engineering team provided thruster data in pound-force seconds (imperial) while the receiving software expected newton-seconds (metric) — a factor-of-4.45 error. The spacecraft entered the Martian atmosphere at the wrong angle and burned up. It remains the most cited real-world consequence of unit conversion failure. This is why engineers, scientists, and developers should always verify units explicitly — and why tools like this converter exist: to eliminate "just trust my memory" arithmetic from important calculations.

All conversions on this tool are formula-based and use full-precision factors sourced from NIST (National Institute of Standards and Technology) and the BIPM (International Bureau of Weights and Measures) — the global authorities on measurement standards. Results are not rounded during calculation; rounding is only applied to the displayed output, and you can see more decimal places when needed. For everyday tasks, cooking, and engineering estimates this is more than sufficient. For legal metrology, clinical dosing, or calibration work, always verify against your field's official standards documentation.