Unit Converter - Fast & Accurate
Convert between 50+ units across 8 categories including length, weight, volume, temperature, area, speed, data, and time. Our free unit converter provides instant results with conversion formulas for everyday calculations.
Unit Converter Calculator
How to Use the Unit Converter
Our unit converter is designed to be simple and intuitive. Follow these steps to convert between any units quickly.
Select a Category
Choose from length, weight, volume, temperature, area, speed, data, or time measurement categories to begin your conversion.
Enter Your Value
Type the numerical value you want to convert in the "Convert From" input field.
Choose Units
Select the source and target units from the dropdown menus. You can use the swap button to reverse the direction of conversion.
View Results
Instantly see your conversion result, including the formula used and other equivalent conversions.
Common Unit Conversion Scenarios
Our unit converter helps with a wide range of everyday tasks. Here are some common scenarios where it proves useful.
Cooking and Baking
Convert between cups, tablespoons, milliliters, and other cooking units when working with international recipes.
International Travel
Convert temperatures between Fahrenheit and Celsius, distances between miles and kilometers, or weights between pounds and kilograms.
DIY Projects
Convert between inches, feet, centimeters, and meters for home improvement and craft projects.
Fitness and Health
Convert between pounds and kilograms for fitness tracking, or between different volume units for medication dosages.
Digital Storage
Convert between bytes, kilobytes, megabytes, gigabytes, and terabytes when working with file sizes and storage capacity.
Science and Education
Convert between scientific units for homework, research, or educational projects across different measurement systems.
Common Unit Conversion Tables
Quick reference tables for the most frequently used unit conversions. Bookmark this page for easy access to these valuable conversion factors.
Length Conversions
| From | To | Multiply By |
|---|---|---|
| Inches | Centimeters | 2.54 |
| Feet | Meters | 0.3048 |
| Yards | Meters | 0.9144 |
| Miles | Kilometers | 1.60934 |
| Meters | Feet | 3.28084 |
Weight Conversions
| From | To | Multiply By |
|---|---|---|
| Pounds | Kilograms | 0.453592 |
| Ounces | Grams | 28.3495 |
| Kilograms | Pounds | 2.20462 |
| Grams | Ounces | 0.035274 |
| Stone | Kilograms | 6.35029 |
Volume Conversions
| From | To | Multiply By |
|---|---|---|
| US Gallons | Liters | 3.78541 |
| US Quarts | Liters | 0.946353 |
| US Cups | Milliliters | 236.588 |
| Liters | US Gallons | 0.264172 |
| Fluid Ounces | Milliliters | 29.5735 |
Temperature Conversions
| From | To | Formula |
|---|---|---|
| Celsius | Fahrenheit | (°C × 9/5) + 32 |
| Fahrenheit | Celsius | (°F - 32) × 5/9 |
| Celsius | Kelvin | °C + 273.15 |
| Kelvin | Celsius | K - 273.15 |
| Fahrenheit | Kelvin | (°F - 32) × 5/9 + 273.15 |
Our unit converter automatically applies these conversion factors for you, saving time and ensuring accuracy.
Frequently Asked Questions
Get answers to common questions about our unit converter and how it works.
How accurate is this unit converter?
Our unit converter uses standard conversion factors and formulas with high precision. For most practical purposes, the results are accurate to at least six decimal places, which is sufficient for nearly all everyday applications.
Can I convert between imperial and metric units?
Yes, our converter handles both imperial and metric units, allowing you to easily convert between them. This includes conversions between feet/inches and meters/centimeters, pounds and kilograms, gallons and liters, and more.
Does this converter work offline?
The unit converter runs in your browser and performs calculations locally once loaded. However, you need an internet connection to initially access the page. For consistent offline access, consider bookmarking the page or using a dedicated app.
Why do temperature conversions use different formulas?
Unlike other unit types that use simple multiplication, temperature scales have different zero points. This requires more complex formulas: Celsius to Fahrenheit uses (C × 9/5) + 32, Celsius to Kelvin uses C + 273.15, and other temperature conversions have their specific formulas.
Can I convert multiple units at once?
Yes, when you convert a value, our tool automatically shows conversions to other units within the same category under "Other Conversions." You can click "Show All" to see all possible conversions for that category.
History of Measurement Units
Understanding the evolution of measurement systems helps appreciate why we have so many different units today.
Ancient Measurement Systems
Early measurement units were based on human body parts or everyday objects. The Egyptian cubit was based on the forearm length, while the Roman foot (pes) was exactly what it sounds like. These naturally varied between regions and cultures, making standardization necessary as trade expanded.
The ancient Egyptians, Mesopotamians, Romans, and Chinese all developed sophisticated measurement systems that laid the groundwork for modern units. Many of our current imperial measurements can trace their origins to these ancient systems.
The Birth of the Metric System
The metric system originated during the French Revolution in the late 18th century. The revolutionary government sought to replace the chaotic old system with one based on nature and reason. Their new system was decimal-based (using powers of 10) and used the meter as its foundation.
The original definition of the meter was one ten-millionth of the distance from the North Pole to the Equator along a meridian passing through Paris. This scientific approach was revolutionary and formed the basis for the International System of Units (SI) we use today.
Imperial System Development
The imperial system, used primarily in the United States today, evolved from English units that were standardized in the British Weights and Measures Act of 1824. These measurements have complex relationships (12 inches in a foot, 3 feet in a yard, 1760 yards in a mile) because they evolved organically over centuries.
While seemingly arbitrary today, these relationships were practical for their time. For example, 12 inches in a foot allows easy division by 2, 3, 4, and 6, which was useful for trades and construction before decimal calculations were common.
Modern Standardization
Today, measurement units are defined with incredible precision using universal physical constants. For example, since 2019, the meter is defined by the distance light travels in a vacuum during 1/299,792,458 of a second, with the second itself defined by atomic oscillations of cesium-133.
The International System of Units (SI) provides a coherent system of measurement used by scientists worldwide and officially adopted by nearly all countries. The United States remains one of the few countries still primarily using customary units (derived from the imperial system) for everyday measurements, though even the U.S. officially defines its customary units in terms of SI units.
Unit Conversion Tips & Tricks
Master unit conversions with these helpful techniques and common conversion factors to remember.
Quick Approximations
- 1 inch ≈ 2.5 centimeters (actual: 2.54)
- 1 kilogram ≈ 2.2 pounds (actual: 2.20462)
- 1 mile ≈ 1.6 kilometers (actual: 1.60934)
- 1 liter ≈ 1 quart (actual: 1.05669 quarts)
- 1 gallon ≈ 3.8 liters (actual: 3.78541)
Memorable Temperature Points
- Freezing point of water: 0°C = 32°F = 273.15K
- Room temperature: 20-25°C = 68-77°F
- Body temperature: 37°C = 98.6°F
- Boiling point of water: 100°C = 212°F = 373.15K
- At -40 degrees, Celsius equals Fahrenheit (-40°C = -40°F)
Chain Conversion Method
When converting between complex units, break the conversion into steps using known conversion factors. For example, to convert square feet to square meters:
- Convert feet to meters: 1 foot = 0.3048 meters
- Square both sides: 1 square foot = (0.3048)² square meters
- Calculate: 1 square foot = 0.092903 square meters
Dimensional Analysis
Use units like algebraic quantities that can cancel out. For example, to convert 65 miles per hour to meters per second:
Notice how "miles" and "hours" cancel out, leaving "meters/second" as the final unit.
Pro Tip: Using Our Calculator
While these manual conversion methods are useful to understand, our unit converter automates these calculations for you. For the most accurate results without memorizing conversion factors, simply use the calculator at the top of this page!
Why Use Our Tool
Our unit converter offers several advantages over other conversion tools. Here's why you should use it for all your conversion needs.
Comprehensive Unit Coverage
Our converter includes 8 categories and over 50 units, covering everything from basic length and weight conversions to more specialized measurements like data storage and temperature.
Instant Calculations
Get results in real-time as you type, with no need to click a calculate button. This allows for quick experimentation with different values and units.
Transparent Formulas
We show you exactly how each conversion is calculated with clear formulas, helping you understand the mathematical relationship between different units.
Mobile-Friendly Design
Our converter works perfectly on smartphones and tablets, allowing you to perform unit conversions anywhere, anytime, without downloading an app.
No Installation Required
Use our converter directly in your web browser without downloading or installing any software or apps. It works on all major browsers and devices.
Time-Saving
Our optimized interface helps you perform conversions in seconds rather than minutes, saving you valuable time on calculations for work, study, or everyday tasks.