Common metric & imperial reference factors
| Measurement | Standard Conversion Factor | Practical Rule of Thumb |
|---|---|---|
| Miles to Kilometers | 1 mi = 1.60934 km | Multiply miles by 1.6 (e.g. 50 mi ≈ 80 km) |
| Inches to Centimeters | 1 in = 2.54 cm | Multiply inches by 2.5 |
| Pounds to Kilograms | 1 lb = 0.453592 kg | Divide pounds by 2.2 (e.g. 150 lbs ≈ 68 kg) |
| US Gallons to Liters | 1 gal = 3.78541 L | Multiply gallons by 3.8 |
| Celsius to Fahrenheit | °F = (°C × 9/5) + 32 | Double °C and add 30 for a quick rough estimate |
Frequently asked questions
What is the difference between a US gallon and an Imperial gallon?
A US liquid gallon is exactly 3.785411784 liters, whereas an Imperial gallon (historically used in the UK and Canada) is significantly larger at exactly 4.54609 liters (approx. 20% larger).
What is the base unit used for conversions?
All length measurements are mathematically normalized through the SI base meter (m), mass through the kilogram (kg), and volume through the liter (L) to ensure maximum floating-point precision.