The Mathematics of Metric & Imperial Weight Conversion
Mass is a measure of the amount of matter in an object, while weight is the gravitational force acting upon that mass (W = m × g). The International System of Units (SI) defines the kilogram (kg) as the base unit of mass, defined via the Planck constant (h = 6.62607015 × 10-34 kg·m²/s).
Mass & Weight Conversion Governing Equation
Target Mass=Source Mass ×
Source Unit to Kilogram Factor (kfrom)Target Unit to Kilogram Factor (kto)
Exact Legal Conversion Multipliers (NIST Standards)
1 lb = 0.45359237 kg (exact)|1 oz = 28.349523 g (exact)|1 stone = 14 lb = 6.35029 kg|1 US ton = 2,000 lb = 907.185 kg
Step-by-Step Calculation Breakdown
Example 1: Convert 75 Kilograms to US Pounds (lb)
1. Conversion ratio: 1 kg ≈ 2.20462262 lbs.
2. Set up multiplication: Pounds = 75 kg × 2.20462262 lb/kg
3. Execute multiplication: 75 × 2.20462262 = 165.346697 pounds (or 165 lb 5.5 oz)
Example 2: Convert 8 Ounces of Flour to Grams
1. Conversion ratio: 1 oz = 28.349523 grams.
2. Multiply: 8 oz × 28.349523 g/oz = 226.796 grams.
Weight & Mass Unit System Reference Matrix
| Unit Name | Symbol | System | Value in SI Kilograms (kg) |
|---|---|---|---|
| Metric Ton | t | Metric / SI | 1000 kg |
| Kilogram | kg | Metric / SI | 1 kg |
| Gram | g | Metric / SI | 0.001 kg |
| Milligram | mg | Metric / SI | 0.000001 kg |
| Pound | lb | US Customary | 0.453592 kg |
| Ounce | oz | US Customary | 0.0283495 kg |
| Stone | st | UK Imperial | 6.35029 kg |
| US Ton | ton | US Customary | 907.185 kg |