Unit Converter

Free online unit converter

This unit converter changes a value from one unit of measurement to another in ten categories: length, weight (mass), temperature, area, volume, speed, time, data storage, pressure and energy. Choose a category, pick the "from" and "to" units, and type a number in either box – the conversion works both ways, instantly. You also get the conversion formula, a ready-made conversion table and the same value expressed in every other unit, so this online unit converter doubles as a unit conversion chart you can read at a glance.

All factors are exact where an exact definition exists (1 inch = 2.54 cm, 1 pound = 0.45359237 kg, 1 acre = 4,046.8564224 m²) and use internationally accepted values elsewhere, so you can trust the answer for school work, cooking, engineering and property deals.

How to use the unit converter

1. Pick what you want to convert – for example Length for a unit converter meter to feet, or Area for land.
2. Choose the unit you have in the From list and the unit you want in the To list.
3. Type your value. Type in the right-hand box instead to convert in the opposite direction, or press ⇄ to swap the units.
4. Read the result, the one-unit formula and the conversion table below the boxes.

Unit conversion formula

Almost every conversion is a multiplication by a fixed factor. The unit converter first changes your value into the category's base unit, then into the target unit:

Result = Value × (factor of "from" unit ÷ factor of "to" unit)

For example, to convert 5 feet to metres: 5 × 0.3048 = 1.524 m. To go from metres to feet, divide by 0.3048 (or multiply by 3.28084). Temperature is the exception because the scales have different zero points – see the temperature formulas below.

Length unit converter

The length converter covers metric units (mm, cm, m, km, µm) and imperial units (inch, foot, yard, mile) plus the nautical mile. Common length conversions:

Weight unit converter

Convert kg to pounds, grams, ounces, stone, tonnes and Indian units such as quintal and tola. One kilogram equals 2.20462 pounds; one pound is exactly 0.45359237 kg. A quintal to kg conversion is simple – 1 quintal = 100 kg, and 10 quintals make 1 metric ton, which answers the common "quintal to metric tons" question. For kg to ton, 1,000 kg = 1 tonne (metric ton), while a US short ton is 907.18 kg. A tola, used for gold in India, is 11.6638 g.

Newton to kg and kg to litre

Newtons measure force, not mass, so a "newton to kg" conversion depends on gravity: on Earth, 1 kgf = 9.80665 N, so 1 N ≈ 0.102 kg-force and 1 kN ≈ 102 kg. Likewise "kg to liter" (or liter to kg, gram to ml) depends on density: for water 1 kg = 1 L and 1 g = 1 mL, but 1 L of milk weighs about 1.03 kg and 1 L of cooking oil about 0.92 kg. Divide the mass by the density to get volume.

Temperature converter

°F = °C × 9/5 + 32  ·  °C = (°F − 32) × 5/9  ·  K = °C + 273.15

Normal body temperature of 37 °C is 98.6 °F; water boils at 100 °C (212 °F) and freezes at 0 °C (32 °F). At −40 the Celsius and Fahrenheit scales meet. The converter blocks values below absolute zero (0 K).

Area and land unit converter

The unit converter for area handles square metres, square feet, square yards (gaj), hectares, acres, square kilometres and square miles, plus land units used in India – cent and guntha. Key land conversions:

So hectare to acre: 1 ha = 2.47105 acres; hectare to square feet: 1 ha = 1,07,639 sq ft; square meter to square feet: multiply by 10.7639; square meter to cent: divide by 40.4686; guntha to square meter: multiply by 101.17. A bigha is not included because its size differs from state to state and even district to district – for example about 1,338 m² (14,400 sq ft) in Assam and West Bengal but about 2,529 m² (27,225 sq ft) for a pucca bigha in Rajasthan – so check the local value with your revenue office before converting bigha to acre or hectare to bigha. For shapes, use the area calculator.

Volume, speed and time conversions

Volume covers litres, millilitres, cubic metres, cubic feet, US and UK gallons, fluid ounces, cups, tablespoons and teaspoons – useful for baking, where 1 US cup = 236.6 mL and 1 tablespoon = 14.8 mL. For tanks and containers, the volume calculator works out the capacity first.

The speed or velocity converter switches between km/h, m/s, mph, knots, ft/s and Mach: divide km/h by 3.6 to get m/s, and 1 mph = 1.609 km/h. For travel time, pair it with the speed distance time calculator. The time converter goes from milliseconds up to years (365.2425 days, the Gregorian average).

Data storage, pressure and energy units

Data storage

Storage makers use decimal units (1 GB = 1,000,000,000 bytes), while Windows reports binary units (1 GiB = 1,073,741,824 bytes). That is why a "1 TB" drive shows about 931 GB. Internet speeds are in bits: 100 Mbps moves 12.5 megabytes per second.

Pressure

Convert bar to psi (1 bar = 14.5038 psi), kPa, MPa, atm, mmHg and kgf/cm². Car tyre pressure of 32 psi is 2.21 bar; normal blood pressure is measured in mmHg.

Energy and electricity units

One unit on your electricity bill is 1 kWh = 3.6 million joules = 3,412 BTU. Food energy is in kilocalories: 1 kcal = 4.184 kJ. Want to know what those units cost? The electricity bill calculator turns watts and hours into units and rupees. To calculate units of electricity, multiply the appliance's watts by the hours it runs and divide by 1,000 – a 1,500 W heater used for 2 hours uses 3 units (kWh).

Metric vs imperial: why unit conversion matters

India and most of the world use the metric (SI) system, but inches, feet and pounds still appear in property listings, screen sizes, body height and imported product specs, and the US uses customary units almost everywhere. A small mistake – mixing up US and UK gallons, or MB and MiB – can cost money or cause errors, which is why this unit converter shows the exact factor behind every answer.

Unit converter list: what you can convert here

The full unit converter list covers length, weight, temperature, area and land, volume, speed, time, data storage, pressure and energy. Each category has its own From and To lists, so pick the category first and the matching units appear.

Unit converter table for everyday conversions

Unit converter inch to feet, cm and mm

There are 12 inches in a foot, so divide inches by 12 for feet: 66 inches is 5.5 feet, or 5 ft 6 in. For metric, the inch is defined as exactly 25.4 mm, which makes inch to cm × 2.54 and inch to meter × 0.0254 in the unit converter.

Unit converter meter to yard and square meter to feet

A yard is 0.9144 m, so one metre is 1.0936 yards – a 100 m race is about 109 yards. In property listings, square meter to feet really means square metres to square feet: multiply by 10.7639, so a 90 m² flat is about 969 sq ft. In the unit converter, hectare to square feet works the same way with a factor of 107,639.

Unit converter bigha to acre

A bigha has no single size, which is why the land list leaves it out. To convert, first find your local bigha in square metres and divide by 4,046.86 (the square metres in one acre). An Assam or West Bengal bigha of about 1,338 m² is roughly 0.33 acre (3 bigha ≈ 1 acre), while a Rajasthan pucca bigha of about 2,529 m² is about 0.625 acre. Enter your bigha's area in square metres in the area converter to get acres, hectares or guntha.

Unit converter quintal to kg and kg to ton

One quintal is 100 kg and one metric ton (tonne) is 1,000 kg, so 25 quintals of wheat is 2,500 kg or 2.5 tonnes. A US short ton is 907 kg and a UK long ton is 1,016 kg, which matters when reading imported specifications.

Unit converter kg to liter and gram to ml

Kilograms measure mass and litres measure volume, so you need the density of the substance. For water 1 kg is 1 litre and 1 g is 1 ml; milk is about 1.03 kg per litre, so 1 kg of milk is about 0.97 litre, and cooking oil is about 0.92 kg per litre, so 1 kg of oil is about 1.09 litres. Divide the mass by the density to get the volume.

Unit converter newton to kg: force vs mass

A newton is a unit of force. On Earth a 1 kg mass weighs 9.81 N, so divide newtons by 9.81 to get the mass in kg (kilogram-force): 500 N is about 51 kg, and 1 kN is about 102 kg. That is also how load ratings on hooks and anchors are converted.

Unit converter velocity: km/h, m/s, mph and knots

Velocity and speed use the same units. Divide km/h by 3.6 for m/s, multiply km/h by 0.6214 for mph, and divide km/h by 1.852 for knots. So 90 km/h is 25 m/s, about 55.9 mph and 48.6 knots.

Unit converter pressure: bar to psi

Tyre pressure in India is usually given in psi, while many European manuals use bar. One bar is 14.5038 psi, so 2.2 bar is about 31.9 psi; divide psi by 14.5038 to go back. 1 atmosphere is 1.01325 bar or 101.325 kPa.

Unit converter for electricity: watt, kWh and joule

Watts measure power and kilowatt-hours measure energy. One unit on an electricity bill is 1 kWh, which equals 3.6 million joules (3.6 MJ). To calculate units of electricity consumed, multiply watts by hours and divide by 1,000: a 1,500 W heater for 2 hours uses 3 kWh, or 3 units.

Unit converter with solution: step by step

Every result on this page shows the factor used, so you can write out the solution. For example, to convert 5 miles to km: (1) find the factor, 1 mile = 1.609344 km; (2) multiply, 5 × 1.609344 = 8.04672; (3) round to a sensible accuracy, 8.05 km. For temperature, use the formula instead of a factor: °F = °C × 9/5 + 32, so 37 °C is 98.6 °F.

Unit converter calculator vs doing it by hand

For one-off questions, mental maths is fine: 1 kg is about 2.2 lb, 1 inch is 2.54 cm. For exact answers, or chains such as square feet to hectares, the unit converter calculator avoids rounding errors because it converts through a base unit with the full factor.

Unit conversion: money and currency

A unit converter for money works differently from length or weight, because exchange rates change every minute. In any unit converter, rupees, dollars or rand are converted by multiplying the amount by the current exchange rate: at a rate of 1 USD = ₹85, $200 is ₹17,000. This page does not show live rates, so take the rate from your bank or the RBI reference rate.

Currency converter ZAR to USD, yen and other pairs

A currency converter from ZAR to USD, yen to USD or zloty to euro uses the same formula: amount × rate. The only thing that differs is where the rate comes from and how fresh it is.

Currency converter monthly average and yearly average rates

Accountants often use a currency converter with a monthly average or yearly average rate instead of the daily rate, for example to convert foreign income for a tax return. Average the daily reference rates for the month or year, then multiply your amount by that average.

Unit converter in JavaScript

This page itself is a unit converter in JavaScript. The core idea fits in a few lines: store every unit as a factor to one base unit, convert the value to the base and then to the target.

const length = { mm: 0.001, cm: 0.01, m: 1, km: 1000, in: 0.0254, ft: 0.3048, yd: 0.9144, mi: 1609.344 };
const convert = (v, from, to) => v * length[from] / length[to];
convert(66, 'in', 'ft');   // 5.5

Temperature is the one category that needs formulas instead of factors, because the scales have different zero points. There is no unit converter free download or app to install – bookmark the page and it works on any phone or PC.

Frequently asked questions

Last updated 2026-09-18