Unit Converter

How the Unit Converter Works

Our universal unit converter handles six common measurement categories: length, weight, temperature, volume, area, and speed. Select a category, enter a value, choose your source and target units, and the result updates instantly as you type.

Supported Categories

• Length: meters, kilometers, centimeters, millimeters, inches, feet, yards, and miles.
• Weight: kilograms, grams, milligrams, pounds, ounces, and metric tons.
• Temperature: Celsius, Fahrenheit, and Kelvin (with offset-based conversion).
• Volume: liters, milliliters, gallons, quarts, pints, cups, and fluid ounces.
• Area: square meters, square kilometers, square centimeters, square feet, square inches, acres, and hectares.
• Speed: meters per second, kilometers per hour, miles per hour, and knots.

How Conversions Are Calculated

Most units convert through a base unit using a multiplication factor. For example, length conversions pass through meters — 1 mile equals 1,609.344 meters, so 1 mile equals 1,609.344 meters divided by 0.0254 to get inches. Temperature is the exception: because Celsius, Fahrenheit, and Kelvin have different zero points, the converter first translates the input to Celsius (applying both a scale and an offset) and then converts to the target unit.

Why Use a Unit Converter?

• International work: Switch between metric and imperial units for engineering, cooking, or travel.
• Education: Verify homework and understand unit relationships.
• Everyday tasks: Convert recipe measurements, body weight, or driving speeds quickly.
• Professional use: Ensure accuracy in construction, science, and logistics calculations.

Conversion Formulas and Reference Factors

Every non-temperature category uses a single base unit and a set of exact conversion factors. For length, the base is the meter: 1 inch = 0.0254 m, 1 foot = 0.3048 m, 1 yard = 0.9144 m, and 1 mile = 1,609.344 m. For weight, the base is the kilogram: 1 pound = 0.45359237 kg and 1 ounce = 0.028349523125 kg. For volume, the base is the liter: 1 US gallon = 3.785411784 L, 1 quart = 0.946352946 L, and 1 US cup = 0.2365882365 L. Area conversions pass through square meters (1 acre = 4,046.8564224 m², 1 hectare = 10,000 m²), and speed conversions pass through meters per second (1 mph = 0.44704 m/s, 1 knot = 0.514444 m/s). All factors follow internationally agreed definitions, so results are exact — only the display is rounded.

Temperature Conversion Explained

Temperature is the one category that cannot be converted with a simple multiplication factor because the Celsius, Fahrenheit, and Kelvin scales have different zero points. To convert Fahrenheit to Celsius, subtract 32 and multiply by 5/9: °C = (°F − 32) × 5/9. To convert Celsius to Fahrenheit, multiply by 9/5 and add 32: °F = °C × 9/5 + 32. Kelvin shifts from Celsius by exactly 273.15: K = °C + 273.15. For example, 98.6 °F converts to (98.6 − 32) × 5/9 = 37 °C, which equals 310.15 K. The converter applies both the scale and the offset in a single step, so you never have to remember the formulas.

Practical Examples

Here are some everyday conversions that show the tool in action:

• Recipe scaling: A European recipe calls for 500 mL of milk. That equals 2.11 US cups or 1.05 US quarts.
• Road trip: A speed limit of 65 mph equals about 104.6 km/h — handy when driving in a metric country.
• Body weight: Someone weighing 180 lb weighs about 81.65 kg, or 81,647 mg for a precise medication dose.
• Land area: A 2.5-acre plot equals roughly 1.01 hectares or 10,117 m² — useful when comparing international real estate listings.
• Oven temperature: A recipe set to 350 °F converts to about 176.7 °C, which you would round to 180 °C on a European oven.

Tips for Accurate Conversions

Always confirm you are converting within the same category — mixing units from different categories produces meaningless results. Be aware that some units share names but differ by system: a US gallon (3.785 L) is smaller than a UK imperial gallon (4.546 L), and a US ton (907.185 kg) is lighter than a metric tonne (1,000 kg). When precision matters, keep as many decimal places as possible through intermediate steps and round only the final result. The converter displays the value in every unit of the selected category, so you can cross-check the result against a second unit to confirm it is reasonable.