Unit Converter
Instantly convert length, weight, temperature, area, volume, speed and time.
What does this Unit Converter do?
This tool converts a value from one measurement unit to another across seven common categories: Length, Weight, Temperature, Area, Volume, Speed, and Time. Pick a category, choose a From and To unit, and type a number.
The converted figure appears instantly in the result field and in the highlighted result panel, with no page reload and no need to click a separate "convert" button. You can also type directly into the result field and the tool will work backward to fill in the matching value, so the conversion works in both directions from the same pair of fields.
How to Use This Unit Converter?
- Pick a category. Choose Length, Weight, Temperature, Area, Volume, Speed, or Time from the tabs at the top of the tool.
- Select your From unit. Choose the unit you already have your value in from the first dropdown.
- Select your To unit. Choose the unit you want to convert into from the second dropdown.
- Enter the value. Type your number into the Value field and the Result updates as you type.
- Copy or edit the result. Use the Copy button to grab the converted figure, or type into the Result field to see the matching Value calculated in reverse.
- Swap or reset. Tap the swap icon to flip the From and To units, or use Reset to clear the fields and start a new conversion.
Built-In Features
Seven Conversion Categories
Switch between Length, Weight, Temperature, Area, Volume, Speed, and Time using the tabs, each with its own set of relevant units loaded automatically.
Two-Way Live Conversion
Typing in the Value field updates the Result, while typing directly into the Result field recalculates the Value, so either box can be the starting point for quick and easy calculations.
One-Tap Unit Swap
The swap button flips the From and To units in one click, carrying the current numbers across so you can see the reverse conversion right away.
Copy Result Instantly
The Copy button on the result panel places the converted number and its unit straight onto your clipboard, ready to paste wherever you need it.
Clear Input Validation
If you type something that is not a valid number, the field is outlined and a short message explains what needs to be fixed before a result is shown.
Keyboard-Friendly Tabs
Category tabs can be moved through with the arrow keys and selected with Enter or Space, so the tool is easy to use without a mouse.
How Unit Conversion Works
Not every category converts the same way. Most units in this tool convert through a simple factor, while temperature needs its own formula because its three scales do not start counting from the same zero point.
Factor-Based Conversion
Length, weight, area, volume, speed, and time all convert through a fixed factor stored against each unit. Your value is multiplied by the From unit's factor and divided by the To unit's factor, which is what lets the same logic handle a mile, a foot, or an inch without separate formulas for each.
Temperature Formula Conversion
Celsius, Fahrenheit, and Kelvin each start their zero point at a different place, so the tool first converts your entered value to Celsius as a common middle step, then applies the correct formula to reach Fahrenheit or Kelvin from there for accurate and consistent results every time.
Results are rounded to keep them readable rather than showing every possible decimal place. Most conversions display up to eight significant figures, while very large or very small numbers are shortened further so the result panel never overflows with an unreadable string of digits.
How to Convert Units Manually (Without a Calculator)
Sometimes you just want the formula so you can work a conversion out on paper or check a number quickly. The steps below are the same logic this tool runs automatically, laid out so you can do it by hand.
- Find the conversion factor. Every non-temperature unit has a fixed factor relative to a base unit, such as 1 mile equaling 1.60934 kilometers.
- Multiply to go from a smaller-factor unit to a larger one. To turn miles into kilometers, multiply your figure by 1.60934.
- Divide to go the other way. To turn kilometers back into miles, divide by 1.60934 instead of multiplying.
- Use a formula for temperature. Celsius to Fahrenheit is (C × 9/5) + 32, and Fahrenheit to Celsius is (F − 32) × 5/9, since temperature scales don't share the same zero point.
- Round sensibly. For everyday use, two or three decimal places are usually enough. For precise or scientific work, keep more digits or let the converter above handle the rounding for you.
Which Unit Categories Can You Convert?
Each category tab loads its own list of units, so you only see options that make sense for what you are converting. Here is what is available in each one.
| Category | Units Available |
|---|---|
| Length | Meter, Kilometer, Mile, Foot, Inch |
| Weight | Kilogram, Gram, Pound, Ounce |
| Temperature | Celsius, Fahrenheit, Kelvin |
| Area | Square Meter, Square Kilometer, Acre, Hectare |
| Volume | Liter, Milliliter, Gallon (US) |
| Speed | km/h, mph, m/s |
| Time | Second, Minute, Hour, Day |
Need to work out someone's age in years, months, and days rather than convert a time unit? Our Chronological Age Calculator handles that calculation directly from a birth date.
Metric vs Imperial: Which System Do I Need?
Most of the confusion behind unit conversion comes down to two systems being used side by side. Knowing which one you're starting from makes it easier to pick the right units in the dropdowns above.
Metric System
Built around powers of ten, using meters, kilograms, liters, and Celsius. It's the standard across most of the world, in science, and in international trade.
Imperial and US Customary Units
Uses miles, pounds, gallons, and Fahrenheit. It's still the everyday system in the United States, alongside partial imperial use in the United Kingdom for things like road distances.
If you're reading a recipe, a spec sheet, or a weather report from a different country than your own, that's usually why the units look unfamiliar. Switching the From and To dropdowns to match each system is the quickest way to bridge the two.
Quick Reference: Common Conversions People Search For
These are some of the most frequently searched conversions across the categories this tool covers. Use them as a quick sanity check, or enter your own figure into the converter above for an exact result.
| Conversion | Result |
|---|---|
| 1 mile | 1.60934 kilometers |
| 1 kilogram | 2.20462 pounds |
| 0°C | 32°F |
| 1 liter | 0.264172 gallons (US) |
| 1 hectare | 2.47105 acres |
| 100 km/h | 62.1371 mph |
Common Reasons to Use an Online Unit Converter
Cooking With Foreign Recipes
Turn grams into ounces or milliliters into cups when following a recipe written in a measurement system you don't normally cook with at home or while traveling abroad.
Planning Travel Distances
Work out a road trip’s distance in miles, or convert a forecast’s Celsius reading to Fahrenheit before packing. To share the figures, our WhatsApp Link Generator creates a ready-to-send chat link.
Tracking Fitness Progress
Convert bodyweight between kilograms and pounds, or running pace between km/h and mph, when your app or coach reports numbers in a different system.
DIY and Home Projects
Change feet and inches into meters, or square meters into acres, when a supplier's spec sheet or a plot of land is listed in a unit you are not used to working with regularly.
Useful Tips
Use Swap to Reverse
Instead of re-selecting both dropdowns, tap the swap icon to flip From and To in one move and instantly see the conversion the other way around, without changing any other settings manually.
Start From Either Field
If you already know the target figure you need, type it into the Result field instead of the Value field and the tool will work out the matching starting amount.
Copy Instead of Retyping
Once a result appears, the Copy button saves you from manually retyping the number elsewhere, which also helps avoid missed decimal points and reduces simple input errors.
Switching Categories Clears Fields
Changing category tabs resets the Value and Result fields, as units rarely carry meaningful numbers across categories. For date-based age calculations, use the Chronological Age Calculator
Frequently Asked Questions
Is this unit converter free to use?
Yes. The tool is free, works instantly in your browser, and does not require an account or sign-up.
Which unit categories does this tool support?
Length, Weight, Temperature, Area, Volume, Speed, and Time, each with its own set of units listed in the From and To dropdowns.
Can I convert a value in both directions?
Yes. Type into the Value field to get a Result, or type into the Result field to calculate the matching Value in reverse.
How do I quickly reverse the From and To units?
Click the circular swap button between the two dropdowns to flip them instantly, keeping your current numbers in place.
Can I copy the converted result?
Yes. The Copy button next to the result panel copies the number along with its unit to your clipboard.
Why does the tool say my input is invalid?
This appears when the Value field contains something that is not a recognizable number. Clearing the field and re-entering a plain number resolves it.
Does temperature convert the same way as other units?
No. Celsius, Fahrenheit, and Kelvin use their own formula rather than a simple multiplication factor, because each scale starts counting from a different zero point.
How accurate are the conversion results?
Results are shown to up to eight significant figures for most numbers, with very large or very small results rounded further so they stay easy to read.
Can I enter decimals or negative numbers?
Yes. The Value and Result fields accept decimal numbers, and negative numbers are accepted where they make sense, such as in temperature conversions.
What happens when I switch to a different category?
The unit dropdowns reload with the options for the new category, and the Value and Result fields are cleared so you can start a fresh conversion.
Can I reset the tool without refreshing the page?
Yes. The Reset button clears the current numbers and returns the focus to the Value field so you can begin again.
Does this tool work on mobile devices?
Yes. The layout adjusts for smaller screens, with the category tabs and unit selectors stacking so everything stays easy to tap.
Can I navigate the category tabs with a keyboard?
Yes. Use the arrow keys to move between category tabs and press Enter or Space to select the highlighted one.