Convert length Units
Enter a value and select the units to convert between.
Try an Example
Pick a scenario to see how the calculator works, then adjust the values
Marathon Distance
Convert a marathon distance from kilometers to miles.
Key values: 42.195 km · Length · km to mi
Body Weight
Convert body weight from kilograms to pounds.
Key values: 75 kg · Mass · kg to lb
Room Temperature
Convert a comfortable room temperature from Celsius to Fahrenheit.
Key values: 22 °C · Temperature · °C to °F
Introduction to Unit Converter
Type a value and select two units. The conversion runs immediately — no submit button needed. The converter covers Length, Weight/Mass, Volume, Area, Speed, Pressure, Temperature, Time, Digital Storage, Energy, Frequency, Fuel Economy, Power, Torque, and more. If a unit isn't in the dropdown, the methodology section explains how to chain conversions manually.
Unit conversion is essential for many fields including engineering, architecture, navigation, physics, construction, cooking, medicine, and everyday tasks. This calculator handles a wide range of units from the metric system, imperial/US system, and specialized units for scientific and technical applications.
How to Use
Basic Usage
- Select the type of conversion from the "Conversion Type" dropdown (Length, Weight/Mass, etc.).
- Enter the numerical value you want to convert in the "Value" field.
- Select the source unit from the "From" dropdown menu.
- Select the target unit from the "To" dropdown menu.
- The conversion result will be displayed automatically.
Supported Unit Categories
- Length: Meters, feet, inches, kilometers, miles, etc.
- Weight/Mass: Kilograms, pounds, grams, ounces, etc.
- Volume: Liters, gallons, cubic meters, fluid ounces, etc.
- Area: Square meters, square feet, acres, hectares, etc.
- Speed: Miles per hour, kilometers per hour, meters per second, etc.
- Pressure: Pascal, PSI, bar, atmospheres, etc.
- Temperature: Celsius, Fahrenheit, Kelvin, etc.
- Time: Seconds, minutes, hours, days, weeks, etc.
- Digital Storage: Bytes, kilobytes, megabytes, gigabytes, etc.
- Data Transfer Rate: Bits per second, bytes per second, etc.
- Energy: Joules, calories, kilowatt-hours, BTUs, etc.
- Frequency: Hertz, kilohertz, megahertz, gigahertz, etc.
- Fuel Economy: Miles per gallon, kilometers per liter, etc.
- Plane Angle: Degrees, radians, gradians, etc.
- Power: Watts, kilowatts, horsepower, etc.
- Torque: Newton meters, pound-feet, etc.
- Electric Current: Amperes, milliamperes, etc.
- Illuminance: Lux, foot-candles, etc.
- Angle (Solid): Steradians, square degrees, etc.
- Data Size Rate: Megabytes per hour, gigabytes per day, etc.
- Dynamic Viscosity: Pascal second, poise, etc.
- Radioactivity: Becquerels, curies, etc.
- Resolution: Pixels per inch, dots per inch, etc.
Input Field
The "Value" field accepts any positive number. For convenience, there are quick value buttons (1, 5, 10, 100) that you can click to quickly set common values.
Unit Selection
The unit dropdowns contain a full list of units organized by system (Metric, Imperial/US, and others depending on the category). Simply scroll through the list or type to search for the unit you need.
Interpreting Results
The results section clearly shows the original value in the source unit and the converted value in the target unit. The conversion formula is also displayed, showing the relationship between the two units (e.g., 1 meter = 3.28084 feet).
For very large or very small numbers, scientific notation may be used to display the result in a readable format. The precision of the displayed result adapts based on the magnitude of the numbers.
You can also copy the conversion result to your clipboard by clicking the copy button in the results card.
Methodology and Formulas
Conversions are performed using precise conversion factors between units. Most conversions are done in relation to a base unit for consistency and accuracy:
- For Length: meter
- For Weight/Mass: kilogram
- For Volume: cubic meter or liter
- For Area: square meter
- For Speed: meter per second
- For Pressure: pascal
- For Temperature: kelvin (though special formulas are used, not just conversion factors)
- For Time: second
- For Digital Storage: byte
- For Data Transfer Rate: bit per second
- For Energy: joule
- For Frequency: hertz
- For Fuel Economy: kilometers per liter
- For Plane Angle: radian
- For Power: watt
- For Torque: newton meter
- For Electric Current: ampere
- For Illuminance: lux
- For Angle (Solid): steradian
- For Data Size Rate: byte per second
- For Dynamic Viscosity: pascal second
- For Radioactivity: becquerel
- For Resolution: pixel per meter
Common Conversion Factors by Category
Length
| Unit | Symbol | Meters Equivalent |
|---|---|---|
| Meter | m | 1 |
| Kilometer | km | 1,000 |
| Centimeter | cm | 0.01 |
| Millimeter | mm | 0.001 |
| Foot | ft | 0.3048 |
| Inch | in | 0.0254 |
| Mile | mi | 1,609.344 |
Weight/Mass
| Unit | Symbol | Kilograms Equivalent |
|---|---|---|
| Kilogram | kg | 1 |
| Gram | g | 0.001 |
| Pound | lb | 0.453592 |
| Ounce | oz | 0.0283495 |
| Metric Ton | t | 1,000 |
Volume
| Unit | Symbol | Liters Equivalent |
|---|---|---|
| Liter | L | 1 |
| Milliliter | mL | 0.001 |
| US Gallon | gal | 3.78541 |
| US Quart | qt | 0.946353 |
| Cubic Meter | m³ | 1,000 |
Temperature Conversion Formulas
Temperature conversions use special formulas rather than simple multiplication factors:
| Conversion | Formula |
|---|---|
| Celsius to Fahrenheit | °F = (°C × 9/5) + 32 |
| Fahrenheit to Celsius | °C = (°F - 32) × 5/9 |
| Celsius to Kelvin | K = °C + 273.15 |
| Kelvin to Celsius | °C = K - 273.15 |
| Fahrenheit to Kelvin | K = (°F - 32) × 5/9 + 273.15 |
| Kelvin to Fahrenheit | °F = (K - 273.15) × 9/5 + 32 |
Time
| Unit | Symbol | Seconds Equivalent |
|---|---|---|
| Second | s | 1 |
| Minute | min | 60 |
| Hour | h | 3,600 |
| Day | d | 86,400 |
| Week | wk | 604,800 |
| Month (average) | mo | 2,629,746 |
| Year | yr | 31,536,000 |
Digital Storage
| Unit | Symbol | Bytes Equivalent |
|---|---|---|
| Byte | B | 1 |
| Kilobyte | KB | 1,000 |
| Megabyte | MB | 1,000,000 |
| Gigabyte | GB | 1,000,000,000 |
| Terabyte | TB | 1,000,000,000,000 |
| Kibibyte | KiB | 1,024 |
| Mebibyte | MiB | 1,048,576 |
| Gibibyte | GiB | 1,073,741,824 |
Conversion Formula
To convert from one unit to another, the calculator uses the following approach:
- Convert the source value to the base unit using its conversion factor
- Convert from the base unit to the target unit using the target unit's conversion factor
The general formula is:
For example, to convert 5 feet to meters:
Real-World Applications
Construction and Engineering
- Converting between imperial and metric measurements on building plans
- Calculating material requirements for construction
- Converting pressure measurements in hydraulic and pneumatic systems
- Determining appropriate dimensions for mechanical parts
Science and Education
- Converting units in physics and chemistry problems
- Standardizing measurements for scientific reports
- Teaching the relationship between different measurement systems
- Converting values for lab experiments and research
Cooking and Food
- Converting recipe measurements between metric and imperial units
- Scaling recipes up or down using different volume units
- Converting weights for food portions and nutritional information
- Adapting recipes from different countries with different measurement systems
Travel and Navigation
- Converting between miles, kilometers, and nautical miles
- Understanding speeds in different units (mph, km/h, knots)
- Converting fuel volumes when traveling internationally
- Understanding area measurements for land and properties
Manufacturing and Industry
- Converting specifications between measurement systems
- Working with international suppliers and clients
- Converting pressure readings for industrial equipment
- Ensuring precision in product dimensions
Health and Medicine
- Converting between pounds and kilograms for patient weights
- Converting medication dosages based on weight
- Measuring blood pressure in different units (mmHg, kPa)
- Converting volumes for fluid intake and output monitoring
Frequently Asked Questions
Why are there different unit systems?
Different unit systems evolved independently across cultures and regions. The metric system (SI) was developed in the late 18th century to create a standardized, decimal-based system. The imperial system evolved from traditional English units. Today, the United States is one of the few countries that still primarily uses imperial units, while most of the world has adopted the metric system.
How accurate are the conversions?
The conversions are based on standard, internationally recognized conversion factors and are calculated with high precision. However, displayed results may be rounded for readability. For scientific or highly precise work, always verify the conversion factors being used.
What's the difference between mass and weight?
Mass is a measure of the amount of matter in an object and remains constant regardless of location. Weight is a force that results from gravity acting on mass and varies depending on the gravitational field. On Earth, we often use the terms interchangeably in everyday language, but they are different physical quantities. The converter uses standard Earth gravity for converting between mass and weight units.
Why do some results show in scientific notation?
Very large numbers (like astronomical distances) or very small numbers (like microscopic measurements) are displayed in scientific notation for clarity. For example, 2,500,000,000 meters would be displayed as 2.5 × 10^9 meters.
How do I convert between units not listed in the calculator?
You can perform multi-step conversions using common intermediate units. For example, to convert from a unit A to unit C, you might first convert from A to B, then from B to C. The calculator supports a full list of units, so this shouldn't be necessary for most standard conversions.
Plate
Specialized Calculators
Choose from 23 specialized versions of this calculator, each optimized for specific use cases and calculation methods.
Category
23 CalculatorsLengthLength Converter
Convert between different units of length such as meters, feet, inches, kilometers, and miles.length · distance · meter · +3
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MassWeight Converter
Convert between different units of weight such as kilograms, pounds, grams, and ounces.weight · mass · kilogram · +3
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VolumeVolume Converter
Convert between different units of volume such as liters, gallons, cubic meters, and fluid ounces.volume · liter · gallon · +2
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AreaArea Converter
Convert between different units of area such as square meters, square feet, acres, and hectares.area · square meter · square foot · +2
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SpeedSpeed Converter
Convert between different units of speed such as mph, km/h, and meters per second.speed · velocity · mph · +2
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PressurePressure Converter
Convert between different units of pressure such as Pascal, PSI, bar, and atmospheres.pressure · pascal · psi · +2
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TemperatureTemperature Converter
Convert between different units of temperature such as Celsius, Fahrenheit, and Kelvin.temperature · celsius · fahrenheit · +2
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TimeTime Converter
Convert between different units of time such as seconds, minutes, hours, days, and weeks.time · seconds · minutes · +3
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Digital StorageDigital Storage Converter
Convert between different units of digital storage such as bytes, kilobytes, megabytes, and gigabytes.digital storage · bytes · kilobytes · +3
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Data Transfer RateData Transfer Rate Converter
Convert between different units of data transfer rate such as bits per second, kilobits per second, and megabits per second.data transfer · bandwidth · bits per second · +2
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EnergyEnergy Converter
Convert between different units of energy such as joules, calories, kilowatt-hours, and BTUs.energy · joules · calories · +2
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FrequencyFrequency Converter
Convert between different units of frequency such as hertz, kilohertz, megahertz, and gigahertz.frequency · hertz · kilohertz · +2
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Fuel EconomyFuel Economy Converter
Convert between different units of fuel economy such as miles per gallon, kilometers per liter, and liters per 100 kilometers.fuel economy · mpg · km/l · +2
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Plane AnglePlane Angle Converter
Convert between different units of plane angle such as degrees, radians, and gradians.plane angle · degrees · radians · +2
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PowerPower Converter
Convert between different units of power such as watts, kilowatts, horsepower, and BTU per hour.power · watts · kilowatts · +2
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TorqueTorque Converter
Convert between different units of torque such as newton meters, pound-feet, and kilogram-force meters.torque · newton meter · pound-foot · +2
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Electric CurrentElectric Current Converter
Convert between different units of electric current such as amperes, milliamperes, and kiloamperes.electric current · ampere · milliampere · +2
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IlluminanceIlluminance Converter
Convert between different units of illuminance such as lux, foot-candles, and phots.illuminance · lux · foot-candle · +2
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Angle (Solid)Solid Angle Converter
Convert between different units of solid angle such as steradians and square degrees.solid angle · steradian · square degree · +1
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Data Size RateData Size Rate Converter
Convert between different units of data size rate such as megabytes per hour, gigabytes per day, and terabytes per week.data size rate · MB/h · GB/day · +2
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Dynamic ViscosityDynamic Viscosity Converter
Convert between different units of dynamic viscosity such as pascal-second, poise, and centipoise.dynamic viscosity · pascal-second · poise · +2
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RadioactivityRadioactivity Converter
Convert between different units of radioactivity such as becquerels, curies, and rutherfords.radioactivity · becquerel · curie · +2
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ResolutionResolution Converter
Convert between different units of resolution such as pixels per inch, dots per inch, and pixels per centimeter.resolution · PPI · DPI · +2
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Further plates · 5 Calculators
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Temperature Converter
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