Unit Converter

Length, weight and temperature — pick a category and convert between any two units instantly.

Conversions people use most

• Kilometers ↔ miles: 1 mile = 1.609 km. Quick check: multiply miles by 1.6 for km.
• Kilograms ↔ pounds: 1 kg = 2.205 lb — useful for luggage limits and gym weights.
• Grams ↔ tola: 1 tola = 11.664 g — the standard unit for gold in South Asia, handy alongside our zakat calculator.
• Celsius ↔ Fahrenheit: °F = °C × 9/5 + 32. Body temperature 37 °C = 98.6 °F.
• Feet/inches ↔ centimeters: 1 ft = 30.48 cm, 1 inch = 2.54 cm — the height-form classic.

The two-measurement-system world

Most countries use the metric system (metres, kilograms, Celsius) while the United States and a few others use imperial units (feet, pounds, Fahrenheit). Travel, online shopping, recipes and health forms constantly force you to translate between them, which is exactly what this converter is for.

Conversions that trip people up

Length and weight are simple multiplications (1 mile = 1.609 km, 1 kg = 2.205 lb), but temperature scales don't share a zero, so you must use °F = °C × 9⁄5 + 32 rather than a single factor. In South Asia gold is weighed in tola (1 tola = 11.664 g) — handy when calculating zakat on gold.

Handy conversion factors

Keep these common factors nearby — they cover most everyday conversions:

For anything not listed, the converter above handles length, weight, temperature, volume and area instantly.

Why temperature converts differently

Length and weight conversions are simple multiplications, because zero means the same thing in both systems — nothing weighs zero kg and something else in pounds. Temperature is different: 0°C and 0°F are different temperatures, so the scales are offset as well as differently spaced.

That is why you need °F = (°C × 9/5) + 32 rather than a single multiplier. The 9/5 handles the different step size (a Celsius degree is 1.8 Fahrenheit degrees) and the +32 handles the offset. Going the other way, subtract first: °C = (°F − 32) × 5/9. Subtracting after multiplying is the classic error and throws the answer out by nearly 18 degrees.

One quirk worth knowing: the scales cross at −40, which is the same temperature in both. And a quick field estimate — double the Celsius and add 30 — is close enough for weather (20°C → 70, actual 68).

Conversions that catch people out

A handful of units share a name but not a value, which causes real mistakes in recipes and shipping.

• US vs Imperial gallon — 3.79 L vs 4.55 L. A 20% difference, so fuel-economy figures from US and UK sources are not comparable.
• US vs Imperial pint — 473 ml vs 568 ml. UK pints are noticeably bigger.
• Fluid ounce vs ounce — one is volume, the other weight. They only coincide for water.
• Ton vs tonne — a metric tonne is 1,000 kg; a US short ton is 907 kg; a UK long ton is 1,016 kg.
• Tola — 11.66 g, used for gold across South Asia. Getting this wrong misprices jewellery badly.

Checking a conversion is right

Two habits catch almost every mistake. First, sanity-check the direction: converting to a smaller unit must give a bigger number. Kilometres to miles should shrink (miles are longer); kilograms to pounds should grow. If your answer moved the wrong way, you divided when you should have multiplied.

Second, estimate before you calculate. Miles are roughly 0.6 of a kilometre, a kilogram is about 2.2 pounds, and an inch is about 2.5 cm. If 10 km comes out as 62 miles rather than 6.2, the rough figure catches it instantly — a decimal-place slip is the most common conversion error there is.

Frequently asked questions