How accurate are the conversions?

Conversions use standard SI-defined ratios (e.g., 1 inch = 0.0254 m exactly). Temperature conversions use the standard offset formulas (°F = °C × 9/5 + 32). Results are accurate to JavaScript's 64-bit float precision.

Can I convert temperature units?

Yes. Select the Temperature category and choose from Celsius, Fahrenheit, Kelvin, or Rankine. The converter handles the non-linear offset formulas automatically.

What units are supported?

Length: mm, cm, m, km, in, ft, yd, mi, nautical miles. Weight: mg, g, kg, t, oz, lb, stone. Temperature: °C, °F, K, °R. Volume: ml to gallons. Area: mm² to square miles. Speed: m/s, kph, mph, knots, fps. Other: Nm and ft·lbs torque.

Does this work without internet?

Yes. Once the page loads, all calculations run locally in your browser. You can save it as a bookmark and use it offline.

Why do some conversion results have many decimal places?

Most unit ratios are irrational numbers (e.g., 1 mile = 1609.344 m). The result shows the full precision. Round to your needed decimal places for practical use.

Unit Converter

Convert any unit instantly — length, weight, temperature, volume, area, speed, and more.

From

0.1

1 Millimeter (mm) = 0.1 Centimeter (cm)

Free Online Unit Converter

Zolkit's unit converter supports 7 categories covering dozens of the most common conversions — length, weight, temperature, volume, area, speed, and torque. Pick a category, select your units from the dropdowns, type a value, and see the result instantly. A swap button reverses the conversion direction with one click. Your last-used category and units are remembered locally so the converter is ready when you return.

7 Unit Categories

Convert length, weight, temperature, volume, area, speed, and torque — all the unit conversions you need in one tool.

Instant Conversion

Results update as you type. Switch between units with dropdowns and see the converted value immediately.

Swap Units

Hit the swap button to instantly reverse the conversion direction. Saves time when you need both directions.

Offline-Ready

All conversions are calculated locally in your browser. No internet required after the page loads.

Works on Any Device

Clean, responsive layout that works on phones, tablets, and desktops alike.

Always Free

No account required, no ads, no limits. Convert as many units as you need, whenever you need.

How to Use the Unit Converter

1
Choose a unit category from the tab bar at the top: Length, Weight, Temperature, Volume, Area, Speed, or Other.
2
Select the unit you're converting from and the unit you're converting to using the dropdowns. Type your value and the result appears instantly.
3
Click the swap button (↔) to reverse the conversion direction, or click Copy to save the result to your clipboard.