10 Everyday Unit Conversions Worth Knowing

A few rules of thumb make life easier when a calculator isn’t handy.

Length

• 1 inch ≈ 2.54 cm
• 1 foot ≈ 30 cm
• 1 mile ≈ 1.61 km

Weight

• 1 kg ≈ 2.2 lb
• 1 ounce ≈ 28 g

Temperature

• 0 °C = 32 °F, 100 °C = 212 °F
• Quick estimate: °F ≈ (°C × 2) + 30

For precision, use the Length, Weight and Temperature converters.