Unit Converter
Instant unit converter for length, weight, temperature, area, volume, speed, data, pressure and energy, metric and imperial. Works offline.
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- ✓ 100% free
- ✓ No sign-up
- ✓ No limits
- 🔒 Files never leave your device
How to: Unit Converter
- Pick a category.
- Type a value and choose units.
- See every conversion instantly.
Recipes, travel, shopping, engineering and homework all involve switching between metric and imperial units. This converter uses exact international definitions and updates instantly as you type.
Common uses
- Convert recipe measurements between cups, grams and millilitres.
- Check speeds and distances while travelling.
- Convert units for school, science and engineering work.
Tips for best results
- Bookmark it – it works offline once loaded.
Why exact definitions matter
Since 1959 the inch, foot, yard, pound and other imperial units have been defined exactly in metric terms. This converter uses those exact definitions, so results match engineering references rather than rounded rules of thumb.
Categories included
Length, mass, temperature, area, volume (including US and UK gallons, which differ), speed, data storage, pressure, energy and large-number units. Type in any field and every other unit updates instantly.
Why use FreePDF for Unit Converter?
| FreePDF | Typical upload-based sites | |
|---|---|---|
| What you type is sent to a server | No – stays in your browser | Often |
| Sign-up required | Never | Often for bigger jobs |
| Hourly / daily task limits | None | Common on free plans |
| Works offline after loading | Yes, for most tools | No |
Frequently asked questions
How accurate is it?
Exact international definitions (e.g. 1 in = 2.54 cm, 1 lb = 0.45359237 kg), shown to 10 significant digits.
How accurate is it?
Exact international definitions (e.g. 1 in = 2.54 cm, 1 lb = 0.45359237 kg), shown to 10 significant digits.
Are US and UK gallons different?
Yes. A US gallon is 3.785 L; a UK (imperial) gallon is 4.546 L.
Is Unit Converter really free?
Yes. Every tool on FreePDF is 100% free with no file limits, no sign-up and no watermarks. The site is supported by unobtrusive ads.
Are my files uploaded to a server?
No. FreePDF processes your files directly in your browser using JavaScript. Your documents never leave your device, so they stay completely private.
Does it work on mobile?
Yes. FreePDF works in any modern browser on Android, iPhone, iPad, Windows, Mac and Linux.