Unit Converters
Free online unit converters for length, weight, temperature, area, volume, speed, time, bytes, pressure, power and torque. Accurate and instant.
Free Online Unit Converters – Metric & Imperial
Unit converters change values between metric, imperial and other units using standard conversion factors – ideal for homework, travel, cooking and engineering.
All 12 Free Unit Converters
- Power Converter – Convert power units online instantly with our free power converter.
- Weight Converter – Convert weight and mass units online instantly with our free weight converter.
- Temperature Converter – Convert temperature units online instantly with our free temperature converter.
- Voltage Converter – Convert electric voltage units online instantly with our free voltage converter.
- Area Converter – Convert area units online instantly with our free area converter.
- Length Converter – Convert length and distance units online instantly with our free length converter.
- Byte & Bit Converter – Convert digital storage units online instantly with our free byte converter.
- Time Converter – Convert time units online instantly with our free time converter.
- Pressure Converter – Convert pressure units online instantly with our free pressure converter.
- Speed Converter – Convert speed units online instantly with our free speed converter.
- Volume Converter – Convert volume units online instantly with our free volume converter.
- Torque Converter – Convert torque units online instantly with our free torque converter.
How to Use These Tools
- Enter the value you want to convert.
- Choose the unit you are converting from.
- Choose the unit you want to convert to.
- See the converted value instantly and copy it.
Quick Reference
| From | To | Multiply by |
|---|---|---|
| 1 inch | centimetres | 2.54 |
| 1 foot | centimetres | 30.48 |
| 1 mile | kilometres | 1.609344 |
| 1 kilogram | pounds | 2.20462 |
| 1 US gallon | litres | 3.78541 |
| °C to °F | °F | × 9/5 + 32 |
Why Use Our Unit Converters?
- Many units: Covers metric, imperial and other commonly used units.
- Precise conversion: Uses internationally accepted conversion factors.
- Instant results: Values are converted as soon as you submit.
- Free and unlimited: Convert as many values as you like with the tool.
- Mobile ready: Works smoothly on phones, tablets and desktops.
- Student friendly: Ideal for homework, engineering and everyday tasks.
Tips
- Check that you selected the correct 'from' and 'to' units.
- For scientific work keep extra decimal places and round at the end.
- Remember that some units share names across systems (for example US and UK gallons).
- Bookmark the page for quick daily conversions.
Worked Example
Example: a recipe asks for 2 cups of milk and your jug shows millilitres. One US cup is about 236.6 ml, so 2 cups is roughly 473 ml. For temperature, 180 °C is 180 × 9/5 + 32 = 356 °F.
Glossary
- Metric system
- Decimal-based units such as metres, kilograms and litres.
- Imperial units
- Units such as inches, feet, pounds and gallons.
- Conversion factor
- The number you multiply by to change one unit into another.
- Base unit
- The reference unit a converter uses internally, such as the metre for length.
- Significant figures
- The meaningful digits in a measured value.
Helpful Guides
- How to Convert Celsius to Fahrenheit (Formula + Table)
- How to Convert kg to Pounds and Pounds to kg
- Metric vs Imperial Units Explained with Conversion Tables
- 12 Free Online Unit Converters for Students and Engineers
Frequently Asked Questions
Are these unit converters free?
Yes. Every tool in this category is free to use on pdfseotools.com with no sign-up.
Do the tools work on mobile?
Yes. They work in any modern browser on Android, iPhone, Windows and Mac.
Is my data safe?
Yes. Connections use HTTPS and uploaded files are removed after processing.