Unit Conversion Calculator

How this unit conversion calculator works

Pick a category, length, weight, temperature, or volume, choose your from and to units, and enter a value. The calculator handles length, weight, and volume through a shared base-unit method, and temperature with its own direct formulas, since temperature scales don’t share a simple multiplication factor.

How length, weight, and volume conversions work

Every unit in a category is defined by a conversion factor to one shared base unit (meters for length, kilograms for weight, liters for volume). To convert between any two units, first convert to the base unit, then convert from the base unit to your target:

Result = ( Value × From-unit factor ) ÷ To-unit factor

How temperature conversions work

• Celsius to Fahrenheit: F = C × 9/5 + 32
• Fahrenheit to Celsius: C = (F − 32) × 5/9
• Celsius to Kelvin: K = C + 273.15

Worked examples

• Length: 5 feet to meters: 5 × 0.3048 = 1.524 m
• Weight: 150 lb to kg: 150 × 0.453592 = 68.04 kg
• Temperature: 98.6°F to Celsius: (98.6 − 32) × 5/9 = 37°C
• Volume: 2 gallons (US) to liters: 2 × 3.78541 = 7.57 L

Common mistakes

• Mixing US and imperial UK units, a US gallon and a UK gallon are different sizes, always confirm which system applies.
• Treating temperature as a simple multiplication, unlike length or weight, temperature scales have different zero points, so a direct formula is required.
• Rounding too early in multi-step conversions, which can compound small errors.

Tips

• For quick mental estimates, 1 kg is roughly 2.2 lb, and 1 mile is roughly 1.6 km.
• When precision matters (cooking, medicine, construction), always use the full calculated value rather than a rounded rule of thumb.
• Double-check whether a recipe or spec sheet is using US or metric units before converting.