Convert between metric and imperial units for length, weight, temperature, area, volume, and speed. Your result updates automatically as you type.
Most units are converted through one base unit, like metres for length or kilograms for weight, using a fixed number to multiply by.
Temperature is different. It needs both a scale change and a number added or subtracted, because the zero points of the two scales are not the same.
Standard conversion: Value × conversion factor
Celsius to Fahrenheit: (°C × 9 ÷ 5) + 32
Celsius to Kelvin: °C + 273.15
The unit converter changes a quantity from one unit to another across six categories: length, weight, temperature, area, speed and digital storage. It is built for the mixed units that are common in India, where land is sold in square feet, square yards and acres, height is spoken of in feet and inches, speed limits are in km/h, and product specifications arrive in pounds, ounces or miles.
Students use it for physics and geography problems, home buyers use it to compare carpet areas and plot sizes, travellers convert speeds and distances, and people shopping for phones and laptops compare storage figures. It also lists the value in every other unit of the category, so you can see the same quantity in several units at once.
1. Pick the category and identify the from-unit and to-unit.
2. For every category except temperature, look up each unit's factor relative to the base unit (metre, kilogram, square metre, metre per second or byte).
3. Convert to the base unit: Base value = Value × factor of from-unit.
4. Convert to the target: Result = Base value ÷ factor of to-unit.
5. For temperature, first convert to Celsius, then to the target: °F = °C × 9 ÷ 5 + 32 and K = °C + 273.15.
6. Round only at the end, and sanity check: converting to a smaller unit should give a larger number.
Storing one factor per unit, relative to a base, avoids a separate factor for every pair. With n units, there are only n factors instead of n × (n − 1) pairs. Any conversion becomes two steps: multiply by the from-unit's factor to reach the base, then divide by the to-unit's factor. For example, a foot is 0.3048 m and a yard is 0.9144 m, so feet to yards is × 0.3048 ÷ 0.9144, which is ÷ 3, as expected.
Because area is length times length, area factors are the square of length factors. One foot is 0.3048 m, so one square foot is 0.3048² = 0.09290304 m². One yard is 3 feet, so one square yard is 9 square feet, not 3. This squaring catches many people when they convert plot sizes. The same holds for volume, where factors are cubed. The converter stores exact squared values, so there is no rounding in the factors themselves.
Length, weight and area scales all start at a true zero, so a single multiplication converts them. Temperature scales do not share a zero. 0 °C is 32 °F, and 0 K is −273.15 °C. Converting needs both a scale factor (a Celsius degree is 9/5 of a Fahrenheit degree) and an offset. That is why the converter routes temperature through Celsius with an add-and-multiply formula. A temperature difference, unlike a temperature reading, converts with the factor alone.
In the digital storage category, this converter takes a kilobyte as 1,024 bytes, a megabyte as 1,024 kilobytes and so on, the binary convention used by most operating systems. Storage makers usually label drives in powers of 1,000. That is why a drive sold as 1 TB shows as about 931 GB on a computer. Neither is wrong, but they are different units, and mixing them explains most 'missing space' complaints.
Gurpreet is comparing plots in Mohali. One listing gives a plot size of 1,800 square feet, while the dealer talks in square yards (gaj), so she converts it using the Area category.
Value: 1,800
From: Square Foot
To: Square Yard
Factors relative to the base unit (square metre): Square Foot = 0.09290304, Square Yard = 0.83612736.
Convert to square metres: 1,800 × 0.09290304 = 167.225472 m².
Convert to square yards: 167.225472 ÷ 0.83612736 = 200.
Check: 1 square yard = 9 square feet, and 1,800 ÷ 9 = 200.
Answer: 1,800 square feet = 200 square yards (about 167.23 square metres).
Dividing square feet by 3 instead of 9 to get square yards.
Converting temperature with a single multiplication and forgetting the 32 offset.
Rounding the intermediate base-unit value, which adds error to the final answer.
Comparing drive capacity in decimal gigabytes with the binary figure an operating system shows.
Assuming local land units like bigha or guntha have one fixed value everywhere; they vary by state.
Comparing flat and plot sizes in square feet, square yards, square metres and acres.
Solving physics and geography problems that mix units.
Converting weights and speeds from foreign product specifications.
Checking storage sizes of phones, cards and cloud plans.
Converting body temperature readings between Celsius and Fahrenheit.
Why does temperature need a different formula?
Length and weight scales all start from zero, so one multiplication is enough. But Celsius and Fahrenheit start from different points, so we also need to add or subtract a number, not just multiply.
How accurate are these conversions?
They use the official, internationally agreed conversion numbers, so they are exact for units like inches to centimetres. The result is only rounded when it is shown on screen.