Unit Converter - Length, Weight, Temperature & More
Convert any unit instantly — length, weight, temperature, volume, area, speed, and more. 200+ free unit conversion calculators.
Formula
Value in Target Unit = Value in Source Unit × (Target Factor / Source Factor)
Convert through a base unit. Divide by the source factor to get the base value, then multiply by the target factor. Temperature requires special formulas due to offset scales.
Worked Examples
Example 1: Recipe Conversion
Problem:A European recipe calls for 500 grams of flour. How many cups is that?
Solution:500 grams of flour ≈ 4 cups (all-purpose flour)\n\nNote: Cup measurements vary by ingredient:\n- Flour: ~125g per cup\n- Sugar: ~200g per cup\n- Butter: ~227g per cup\n\nFor precision, weight measurements are preferred.
Result:500g flour ≈ 4 cups
Example 2: Travel Speed Conversion
Problem:A car is traveling at 120 km/h. What is that in mph?
Solution:Conversion factor: 1 km/h = 0.621371 mph\n\n120 km/h × 0.621371 = 74.56 mph\n\nAlternatively:\n120 ÷ 1.60934 = 74.56 mph
Result:120 km/h = 74.56 mph
Example 3: Real Estate Area
Problem:A property listing shows 2,000 square feet. What is that in square meters?
Solution:Conversion: 1 sq ft = 0.092903 sq m\n\n2,000 sq ft × 0.092903 = 185.8 sq m\n\nOr: 2,000 ÷ 10.764 = 185.8 sq m\n\nThis is equivalent to about 1.86 are or 0.0186 hectares.
Result:2,000 sq ft = 185.8 sq m
Frequently Asked Questions
What's the difference between mass and weight?
Mass measures the amount of matter (constant everywhere) in kilograms. Weight is the force of gravity on mass (varies by location) in Newtons. On Earth, we use them interchangeably, but in physics and space, they differ significantly.
What is the difference between mass and weight?
Mass measures the amount of matter in an object (kilograms) and is constant everywhere. Weight is the gravitational force on that mass (newtons) and varies by location. On Earth, a 1 kg object weighs about 9.8 newtons. In everyday use, the terms are often used interchangeably.
How do significant figures affect unit conversions?
Your converted result should have the same number of significant figures as your original measurement. If you measure 5.2 inches (2 significant figures), converting to centimeters gives 13 cm, not 13.208 cm. Using excessive decimal places implies false precision.
What are the most common unit conversion mistakes?
Common errors include confusing fluid ounces with weight ounces, mixing up miles and nautical miles, forgetting that UK and US gallons differ (UK is 20% larger), using the wrong temperature formula, and not accounting for the difference between troy and avoirdupois ounces.