Pounds and ounces
The avoirdupois pound is exactly 0.45359237 kilograms (1959 agreement) and contains 16 ounces. Body weight, food and product weights in the US, and body weight alongside stone in the UK, use pounds.
The avoirdupois ounce is one sixteenth of a pound: exactly 28.349523125 grams. US recipes, food packaging, postage and shipping weights use ounces. It is not the fluid ounce, which measures volume.
Worked example
Convert 2.5 lb: 2.5 × 16 = 40, so 2.5 pounds is 40 ounces. Likewise 2 lb = 32 oz.
Estimating in your head
The factor is a short exact number, so mental math needs no rounding: multiply by 16.
Going the other way
To convert ounces to pounds, divide by 16 (or multiply by 0.0625). The swap button between the boxes opens that page.
How this works
oz = lb × 16
1 lb = 0.45359237 kg and 1 oz = 0.028349523125 kg, both by definition, so the factor is their ratio: 16 exactly. Results drop binary floating-point noise beyond 15 significant digits and display at the precision you choose (6 significant figures by default). Copy result copies the full value.
Frequently asked
How many ounces are in a pound?
1 pound = 16 ounces, exactly. The value follows from the unit definitions, so it never changes.
How do I convert pounds to ounces?
Multiply by 16. For example, 2 lb × 16 = 32 oz.
What is 10 lb in ounces?
10 lb = 160 oz. The table next to the converter lists more common values.
Is the result rounded?
Only on screen. The page computes with the exact definitions and removes floating-point noise past 15 significant digits; pick 3 to 12 significant figures, or use Copy result for the full value.
Sources
- NIST SP 811 Appendix B.8 — Factors for units listed alphabetically
- Federal Register 59-5442 (1959) — Refinement of values for the yard and the pound
- Wikipedia — Avoirdupois system
Reviewed Oct 17, 2026 · test vectors fixtures/units/mass/lbs-to-ounces/