📏 Unit Converter – Instant, Free & Offline
This free unit converter instantly converts length, weight, temperature, area, volume, speed, and data units — entirely in your browser with no upload and no login required.
About
Toolio's Unit Converter covers 7 categories and over 50 units — from millimeters to nautical miles, milligrams to carats, Celsius to Kelvin, hectares to acres, milliliters to tablespoons, knots to Mach, and bits to petabytes. It shows the conversion formula for every calculation so you can understand exactly how the result is derived. Because everything runs client-side, your inputs never leave your device — making it safe to use on sensitive or offline environments.
How to use
- Select a category (Length, Weight, Temperature, Area, Volume, Speed, or Data).
- Choose the source unit from the left dropdown.
- Type your value into the input field — the result updates instantly.
- Choose the target unit from the right dropdown to see the converted value.
- Hit the swap button (⇄) to reverse the conversion, or click Copy to copy the result.
FAQ
- Is this unit converter free?
- Yes, completely free — no account, no subscription, no hidden fees.
- Do you upload my data to a server?
- No. All conversions run entirely in your browser using JavaScript. Nothing is sent to any server.
- Does it work offline?
- Yes. Once the page is loaded, you can disconnect from the internet and all conversions continue to work.
- How do I convert Fahrenheit to Celsius online?
- Select the Temperature category, choose Fahrenheit (°F) as the source unit, enter your value, and select Celsius (°C) as the target — the result and formula appear instantly.
- Which unit categories are supported?
- Length, Weight, Temperature, Area, Volume, Speed, and Data — covering over 50 individual units from metric, imperial, and digital measurement systems.