Unit Converter Guide: How Conversions Work
Whether you're converting kilometers to miles, kilograms to pounds, or Celsius to Fahrenheit, every unit conversion follows the same underlying logic: multiply by a conversion factor equal to 1. This guide shows the method and the special cases where it breaks down.
The Factor-Label Method
The conversion factor is a fraction equal to 1, so multiplying by it changes the units without changing the quantity.
Example: to convert 5 miles to kilometers, multiply by 1.60934 (since 1 mile = 1.60934 km): 5 × 1.60934 = 8.05 km.
Common Conversion Factors
| Quantity | Conversion |
|---|---|
| Length | 1 mile = 1.60934 km; 1 inch = 2.54 cm |
| Weight | 1 lb = 0.453592 kg; 1 oz = 28.3495 g |
| Volume | 1 gallon (US) = 3.78541 L; 1 cup = 236.588 mL |
| Speed | 1 mph = 1.60934 km/h; 1 knot = 1.852 km/h |
Why Temperature Is Different
Most conversions use a single multiplier, but temperature between Celsius, Fahrenheit, and Kelvin requires a formula — because the zero points differ, not just the unit size.
You can't just "multiply by a factor" — you must also shift the zero point.
US gallons (3.785 L) and imperial gallons (4.546 L) are different. Always confirm which one a recipe or spec uses.
Put It Into Practice
Switch between length, weight, volume, temperature, speed, and more — pick a source and target unit and type your value.
无论你是在将公里转换为英里、千克转换为磅，还是摄氏度转换为华氏度，每一次unit conversion都遵循相同的基本逻辑：乘以一个等于1的转换因子。本指南展示了这种方法以及它失效的特殊情况。
因子-标签法
转换因子是一个等于1的分数，所以乘以它会改变单位而不改变数量。
示例：要将5英里转换为公里，乘以1.60934（因为1英里 = 1.60934公里）：5 × 1.60934 = 8.05公里。
常见转换因子
| Quantity | Conversion |
|---|---|
| Length | 1 mile = 1.60934 km; 1 inch = 2.54 cm |
| Weight | 1 lb = 0.453592 kg; 1 oz = 28.3495 g |
| Volume | 1 gallon (US) = 3.78541 L; 1 cup = 236.588 mL |
| Speed | 1 mph = 1.60934 km/h; 1 knot = 1.852 km/h |
为什么温度不同
大多数转换使用单个乘数，但摄氏度、华氏度和开尔文之间的温度转换需要一个公式——因为零点不同，不仅仅是单位大小不同。
你不能只"乘以一个因子"——你还必须移动零点。
US gallons (3.785 L) 和 imperial gallons (4.546 L) 是不同的。始终确认食谱或规格使用的是哪一种。
付诸实践
在长度、重量、体积、温度、速度等之间切换——选择一个源单位和目标单位，然后输入你的值。