Sixteen ounces to the pound
The everyday (avoirdupois) pound is defined as exactly 16 ounces, so this is one of the few conversions with no rounding at all. Half a pound is 8 oz, a quarter is 4 oz — 16 splits in half cleanly, which is the whole reason the system stuck.
Quick reference
| Ounces | Pounds | As lbs & oz |
|---|---|---|
| 4 oz | 0.25 lb | 0 lb 4 oz |
| 8 oz | 0.5 lb | 0 lb 8 oz |
| 12 oz | 0.75 lb | 0 lb 12 oz |
| 16 oz | 1 lb | 1 lb 0 oz |
| 24 oz | 1.5 lb | 1 lb 8 oz |
| 32 oz | 2 lb | 2 lb 0 oz |
| 48 oz | 3 lb | 3 lb 0 oz |
| 64 oz | 4 lb | 4 lb 0 oz |
Newborn weights are the most common "lbs and oz" case: an average US baby is 7 lb 8 oz, and the whole-ounce part is exactly this table's remainder after dividing by 16.
Two traps: fluid ounces and troy ounces
- oz is not fl oz. 16 ounces of mass make a pound; 16 fluid ounces of volume make a pint. For water they roughly coincide, but for flour or butter they do not.
- Troy is different. Precious metals use troy weight, where a pound is 12 ounces, not 16. Oddly, a troy ounce (31.1 g) is heavier than an avoirdupois ounce (28.35 g), yet a troy pound is lighter than a normal pound.
- Metric anchor. 1 oz is about 28 g and 1 lb is about 0.45 kg, useful when a scale reads in one system and you think in the other.
Common questions
How many ounces are in a pound?
Exactly 16 ounces make one pound in the avoirdupois system used for everyday weights. So to go from ounces to pounds you divide by 16, and to go back you multiply by 16.
How do I read "7 lbs 11 oz" as a decimal?
It is not 7.11. The ounces are sixteenths of a pound, so 7 lbs 11 oz is 7 plus 11 divided by 16, which is 7.6875 lbs. To turn it all into ounces, do 7 times 16 plus 11, giving 123 oz.
What is the difference between oz and fl oz?
An ounce (oz) measures mass, about 28.35 grams. A fluid ounce (fl oz) measures volume, about 29.57 mL. They are different quantities that happen to share the word ounce, so 16 oz is a pound but 16 fl oz is a pint.
