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Unit Converter

Convert common everyday, scientific, engineering, and digital units with category-aware selectors, transparent definitions, and a complete equivalents table.

  • metric converter
  • imperial converter
  • measurement conversion
  • length mass temperature volume
  • meters to feet

Changing category resets the source and destination units to a useful common pair.

Use Swap units to reverse the selected pair without changing the entered value.

Status: initial

Results

Awaiting calculation

Unit conversion guide

One conversion workspace for everyday and engineering quantities

The Unit Converter uses a category-first form so source and destination menus contain only compatible units. It covers common metric, US customary, Imperial, scientific, electrical-adjacent, mechanical, digital, and fuel-economy quantities, then shows the selected conversion, base-unit audit, reverse relationship, scientific notation, and every supported equivalent in that category.

Use it to change unit representation without changing the quantity

Use the converter for measurements, coursework, travel, recipes, construction checks, laboratory notes, data-storage comparisons, and preliminary engineering calculations. Conversion does not correct a measurement, change its physical conditions, or make it more precise. Confirm the unit variant and reference basis before consequential work.

Most conversions normalize through one category base unit

For linear units, the calculator multiplies the source value by its base-unit factor and divides by the destination factor. Temperature uses scale-specific offsets, while fuel economy uses reciprocal relationships through litres per 100 kilometres. This separation prevents incorrect one-factor treatment of affine or reciprocal scales.

Variable explanations

Understand what each input and result means before calculating.

🗂️ Measurement category

Choose the physical or digital quantity first. Only units of the same dimension can be converted directly.

🔢 Value

Enter a finite decimal or scientific-notation value. Zero is valid except on reciprocal fuel-economy scales.

➡️ Convert from

Select the unit that actually describes the entered number, including US, Imperial, decimal, binary, or named variant where relevant.

⬅️ Convert to

Select the desired representation. The Swap units button reverses the pair but preserves the entered number.

📏 Base unit

The audit normalizes the source quantity to a stable category base unit before producing the destination value.

🌡️ Temperature

Temperature uses affine conversions with offsets. A temperature difference is not converted by the same formula as an absolute temperature reading.

⛽ Fuel economy

L/100 km measures consumption, while km/L and mpg measure distance per fuel volume. Their relationship is reciprocal.

💾 Digital data

Decimal kB, MB, and GB use powers of 1000; binary KiB, MiB, and GiB use powers of 1024. Bits and bytes differ by eight.

🇺🇸 US vs Imperial

US liquid gallons and fluid ounces are different from Imperial gallons and fluid ounces. Labels remain explicit throughout the results.

🎯 Significant digits

Display precision should reflect the original measurement and conversion-factor status. Exact factors do not make an uncertain input exact.

Reviewed by the Calculator.org.in Editorial Team

Formula behavior, validation cases, explanatory examples, and cited sources are checked before publication. This review supports educational accuracy and is not a substitute for qualified professional advice.

Last reviewed: 2026-08-10

Review process

Formula guide

See the calculation logic, variable definitions, and practical meaning.

Linear unit conversion

x₂ = x₁ × f₁ ÷ f₂

  • f₁ converts the source unit to the category base unit
  • f₂ converts the destination unit to the same base unit

Used for length, area, volume, mass, speed, pressure, energy, power, force, angle, frequency, digital data, acceleration, torque, and density.

Celsius to Fahrenheit

°F = (°C × 9/5) + 32

  • Temperature scales have different zero points

An offset is required; multiplying by a factor alone is wrong.

Fahrenheit to Celsius

°C = (°F − 32) × 5/9

  • Subtract the offset before scaling

The inverse of the Celsius-to-Fahrenheit relationship.

Celsius to kelvin

K = °C + 273.15

  • Kelvin values cannot be negative

The kelvin and degree Celsius have equal interval sizes but different zeros.

US fuel economy

mpgUS = 235.214583 ÷ (L/100 km)

  • Both values must be positive
  • US and Imperial gallons differ

Fuel economy and consumption are reciprocal quantities.

Imperial fuel economy

mpgImp = 282.480936 ÷ (L/100 km)

  • Imperial gallon is larger than US liquid gallon

The same vehicle has different numeric mpg values under the two gallon definitions.

Area conversion

1 ft² = (0.3048 m)² = 0.09290304 m²

  • Length factors must be squared

A common error is applying the unsquared linear factor to area.

Volume conversion

1 ft³ = (0.3048 m)³ = 0.028316846592 m³

  • Length factors must be cubed

Cubic-unit conversions amplify prefix and length-factor changes.

Bits and bytes

1 byte = 8 bits

  • b usually denotes bit
  • B denotes byte

Case matters in digital unit symbols.

Decimal and binary data

1 kB = 1000 B; 1 KiB = 1024 B

  • SI decimal prefixes and IEC binary prefixes are distinct

The converter labels both systems instead of treating them as synonyms.

Common conversion examples

Follow realistic inputs through the calculation step by step.

1

Worked example

Metres to feet

  1. 1Choose Length.
  2. 2Enter 1 metre and select international foot as the destination.
  3. 3The result is approximately 3.2808399 ft; 1 m and 1 ft are exactly defined.
2

Worked example

Kilograms to pounds

  1. 1Choose Mass.
  2. 2Enter 10 kg and select avoirdupois pound.
  3. 3The result is approximately 22.046226 lb.
3

Worked example

Celsius to Fahrenheit

  1. 1Choose Temperature.
  2. 2Enter 20 °C and select °F.
  3. 3The offset formula gives 68 °F.
4

Worked example

Litres to US and Imperial gallons

  1. 1Choose Volume and enter litres.
  2. 2Convert once to US gal and once to Imp gal.
  3. 3Notice that the two gallon results differ because their definitions differ.
5

Worked example

Kilometres per hour to mph

  1. 1Choose Speed.
  2. 2Enter 100 km/h and select mph.
  3. 3The result is approximately 62.137119 mph.
6

Worked example

Bar to psi

  1. 1Choose Pressure.
  2. 2Enter 1 bar and select psi.
  3. 3The result is approximately 14.503774 psi.
7

Worked example

Gigabytes to gibibytes

  1. 1Choose Digital data.
  2. 2Enter 1 GB and select GiB.
  3. 3The decimal gigabyte equals approximately 0.93132257 GiB.
8

Worked example

Fuel consumption to US mpg

  1. 1Choose Fuel economy.
  2. 2Enter 8 L/100 km and select mpg (US).
  3. 3The reciprocal conversion gives approximately 29.401823 mpg (US).

Unit-conversion mistakes

Avoid these common input and interpretation errors.

Converting between incompatible dimensions

A metre cannot be converted directly to a square metre, litre, kilogram, or second without additional physical information.

Using a length factor for area or volume

Area requires the square of a length factor and volume requires the cube.

Treating temperature as a simple ratio

Celsius and Fahrenheit have offsets as well as different interval sizes.

Confusing mass and force

Kilograms and pounds in the Mass category are mass units. Newtons, pound-force, and kilogram-force belong to Force.

Assuming gallon means one universal volume

A US liquid gallon is about 3.785 L, while an Imperial gallon is exactly 4.54609 L.

Confusing fluid ounces with mass ounces

Fluid ounce is volume; avoirdupois ounce is mass. Conversion between them requires a substance density.

Confusing bit and byte

A byte is eight bits, and symbol capitalization commonly distinguishes B from b.

Treating GB and GiB as synonyms

GB is decimal and GiB is binary. Storage systems may report different-looking capacities for the same byte count.

Using US mpg where Imperial mpg is intended

The different gallon definitions make the numbers differ even for identical consumption.

Converting calendar months with one fixed factor

Months and civil years vary. The converter includes fixed seconds, days, weeks, and the explicitly labelled Julian year instead.

Ignoring reference conditions

Density, pressure, standard-volume flow, and material properties may depend on temperature, pressure, composition, or test method.

Adding false precision

A converted value should not imply more measurement certainty than the original input supports.

Frequently asked questions

Quick answers to the questions users ask most often.

How does this unit converter work?
It normalizes the entered value to a category base unit and then converts that base quantity to the selected destination unit. Temperature and fuel economy use dedicated formulas.
Which categories are supported?
Length, area, volume, mass, temperature, speed, time, pressure, energy, power, force, angle, frequency, digital data, data rate, acceleration, torque, density, and fuel economy.
Can I convert metric to Imperial or US customary units?
Yes. Common length, area, volume, mass, speed, pressure, power, force, torque, and density units are included and variants are labelled.
Are the conversion factors exact?
Many are exact definitions, including the international inch, foot, yard, mile, pound, and SI prefixes. Some displayed decimal factors or named conventional units are approximate; the audit identifies their status.
Why do temperature conversions need an offset?
Celsius, Fahrenheit, kelvin, and Rankine do not all share the same zero point, so absolute temperature readings need both scale and offset changes.
Can temperature be below absolute zero?
Not in this model. Inputs that convert to a negative kelvin value are rejected.
What is the difference between US and Imperial gallons?
The US liquid gallon is exactly 3.785411784 L; the Imperial gallon is exactly 4.54609 L.
Is a pound mass or force?
The Mass category uses the avoirdupois pound as mass. The Force category separately uses pound-force.
What is the difference between a bit and a byte?
One byte equals eight bits. Data-rate symbols also distinguish bit/s from B/s.
What is the difference between MB and MiB?
A decimal megabyte is 1,000,000 bytes; an IEC mebibyte is 1,048,576 bytes.
Why are L/100 km and mpg reciprocal?
L/100 km is fuel used per distance, while mpg is distance travelled per fuel volume. Improving economy makes one number fall and the other rise.
Can I convert weight to volume?
Not without knowing the material density and conditions. Mass and volume are different dimensions.
Can I convert watts to watt-hours?
Not without elapsed time. Watts are power; watt-hours are energy.
Why is torque not listed as energy?
Torque and energy share the dimensions N·m, but they represent different physical quantities and should not be treated as interchangeable.
Does unit conversion improve accuracy?
No. It changes representation only. The input uncertainty, resolution, calibration, and physical assumptions remain.
What does the all-equivalents table show?
It expresses the same normalized base quantity in every supported unit of the selected category.
Can I use scientific notation?
Yes. Number inputs such as 1e6 are accepted, and a scientific-notation result is shown separately.

References

Sources used to support the calculator guidance.

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Version history

A transparent record of calculator content updates.

Updated 2026-08-10
  • 1.0.0 · 2026-08-10

    Initial standalone release with 19 category-aware converters, dynamic unit selectors, swap control, base-unit audit, all-equivalents tables, temperature offsets, reciprocal fuel economy, and decimal-versus-binary data definitions.