Free Unit Converter

A unit converter translates measurements between different units across seven major categories: length, weight (mass), temperature, volume, speed, time, and area. It handles dozens of units within each category, displays the conversion factor used, and provides a table of common equivalents so you can see how your value translates across multiple units at once.

Unit conversion comes up constantly — in cooking, construction, science, fitness, travel, and everyday life. Whether you're converting centimeters to inches for a furniture order or Celsius to Fahrenheit for a weather report, this tool gives you instant, accurate results with the math shown.

• Length - Convert between meters, feet, inches, centimeters, kilometers, miles, yards, and more
• Weight - Translate between kilograms, pounds, ounces, grams, stones, and metric tons
• Temperature - Handle Celsius, Fahrenheit, and Kelvin conversions with the correct offset formulas
• Volume - Convert liters, gallons, cups, milliliters, fluid ounces, tablespoons, and other units
• Speed - Switch between mph, km/h, m/s, knots, and feet per second
• Time and area - Convert seconds to hours, square meters to square feet, acres to hectares, and beyond

• Too many factors to memorize - There are hundreds of conversion factors across different unit systems, and remembering them all is impractical
• Temperature conversions aren't linear - Unlike most conversions, temperature requires both multiplication and an offset (e.g., °F = °C × 9/5 + 32), which makes mental math unreliable
• Metric vs. imperial confusion - Switching between systems that use completely different base units leads to frequent errors, especially with less common units
• Compound conversions multiply errors - Converting through intermediate units (e.g., miles → km → meters) compounds rounding errors if you're not careful with precision

Select a measurement category (length, weight, temperature, volume, speed, time, or area), enter your value, and choose the source and target units. The converter applies the appropriate conversion factor (or formula for temperature) and displays the result instantly. It also shows the conversion factor itself and a table of common equivalent values.

For temperature, the converter uses the exact formulas with offsets rather than simple multiplication, ensuring accurate results for Celsius ↔ Fahrenheit ↔ Kelvin conversions.

Example

Converting 100 cm to inches: the converter applies the factor 1 cm = 0.393701 inches, yielding 39.3701 inches. The common equivalents table also shows the value in feet (3.281), meters (1.0), millimeters (1000), and other length units.

• Cooking abroad - Convert recipe measurements from cups and ounces to milliliters and grams when using international recipes
• Travel planning - Switch between miles and kilometers, or Fahrenheit and Celsius, when visiting countries that use different systems
• Fitness tracking - Convert body weight between kilograms and pounds, or running distances between km and miles
• Home improvement - Translate between square feet and square meters when comparing flooring, paint coverage, or room dimensions
• Science and engineering - Convert between SI and imperial units for lab reports, specifications, and calculations

• Seven categories, dozens of units - One tool covers length, weight, temperature, volume, speed, time, and area
• Conversion factor shown - See the exact multiplier or formula used so you can apply it yourself in the future
• Common equivalents table - View your value expressed in multiple units at once, not just the one you selected
• Temperature done right - Uses proper offset formulas rather than simple ratios, so Celsius ↔ Fahrenheit is always accurate
• Free and instant - No downloads, no accounts — select your units and get your answer immediately

What categories are supported?

The converter supports seven categories: length, weight (mass), temperature, volume, speed, time, and area. Each category includes dozens of commonly used units.

Why are temperature conversions different from other conversions?

Temperature scales have offsets (Fahrenheit's zero point is different from Celsius's), so conversion requires both multiplication and addition — not just a simple ratio. The converter applies the correct formulas automatically.

Is the conversion factor shown?

Yes. Every conversion displays the exact factor or formula used, so you can see the math behind the result and apply it manually if needed.

Can it handle compound units like miles per hour?

Yes. The speed category includes compound units like mph, km/h, m/s, knots, and ft/s. The converter treats these as single units with pre-calculated conversion factors between them.

How accurate are the results?

Results are calculated to full floating-point precision and displayed with appropriate significant figures. For scientific and engineering work, the precision is more than sufficient for standard applications.

Is this converter free to use?

Yes, the unit converter is completely free with no limits on conversions, no sign-up required, and no ads.