The formula
g = oz × 28.349523125
Where the factor comes from — each unit by its definition, then its size in SI:
1 oz = lb / 16 = 0.028349523125 kg1 g = kg / 1000 = 0.001 kg
Dividing the two SI sizes gives the factor: 28.349523125, exact — every step above is a definition, not a measurement. The reverse factor is 0.0352739619496.
Physics formulas take mass in kilograms. Pounds (lb) are a unit of mass; pound-force (lbf) is the weight of a pound — a different quantity, on the force page.
Worked examples
- A family car (1500 kg): 52,910.9 oz = 1,500,000 g — 52,910.9 × 28.34952313 = 1,500,000
- An adult (75 kg): 2,645.55 oz = 75,000 g — 2,645.55 × 28.34952313 = 75,000
- A bag of flour (1 lb): 16 oz = 453.592 g — 16 × 28.34952313 = 453.592
- A block of butter: 8.81849 oz = 250 g — 8.81849 × 28.34952313 = 250
Frequently asked questions
How many grams is 1 oz?
1 oz = 28.349523125 g, exactly, from the unit definitions.
How do I convert grams back to ounces?
Divide by 28.349523125 — or multiply by 0.0352739619496: 1 g = 0.0352739619496 oz.