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Weight & Mass Conversion: Kilograms, Pounds & Ounces

Understand the difference between mass and weight, and learn exact ratios for grams, kilograms, pounds, stones, and ounces.

By UnitCompiler Engineering • 4 min read • Published 2026-08-30

Mass vs. Weight

In everyday life, we use “weight” and “mass” interchangeably. However, in physics:

  • Mass is the amount of matter in an object (measured in kilograms).
  • Weight is the force exerted on that mass by gravity (W = m × g).

The international avoirdupois pound is legally defined as exactly 0.45359237 kilograms.

Kilograms to Pounds Formula
Pounds (lbs) = Kilograms (kg) × 2.20462262

For a fast mental estimation: Double the kilograms and add 10% (e.g. 80 kg × 2 = 160; 160 + 16 = 176 lbs)

Ounces to Grams (Avoirdupois)
Grams (g) = Ounces (oz) × 28.349523

1 pound contains exactly 16 ounces

Conversion Reference Table

Weight Conversion Ratios
From UnitTo UnitMultiply ByExample
1 Kilogram (kg) Pounds (lbs) 2.20462 70 kg = 154.32 lbs
1 Pound (lb) Kilograms (kg) 0.453592 180 lbs = 81.65 kg
1 Ounce (oz) Grams (g) 28.3495 8 oz = 226.8 g
1 Stone (st - UK) Pounds (lbs) 14.0 11 st = 154 lbs
1 Metric Tonne (t) Kilograms (kg) 1000.0 2.5 t = 2,500 kg

Precious Metals: Troy Ounces

Gold, silver, and precious stones are weighed in troy ounces (1 oz t ≈ 31.1035 g), which is heavier than a standard avoirdupois ounce (28.35 g).