Ounces to Pounds Converter

Sixteen ounces to the pound — with the fluid-ounce and troy-ounce traps spelled out.

Conversion table

Weight	In pounds
0.5	0.03125 lb
1	0.0625 lb
1.5	0.09375 lb
2	0.125 lb
2.5	0.15625 lb
3	0.1875 lb
4	0.25 lb
5	0.3125 lb
6	0.375 lb
7	0.4375 lb
8	0.5 lb
9	0.5625 lb
10	0.625 lb
12	0.75 lb
15	0.9375 lb

🍼 The numbers to remember

16 oz1 lb
1 oz28.3495 g
1 lb453.592 g
1 troy oz (gold)31.1035 g

Avoiding the classic mix-ups

A fluid ounce measures volume and an ounce measures weight. They are only close for water; 8 fl oz of honey weighs about 12 oz.
Precious metals use the troy ounce, 31.1035 g, which is 10% heavier than the ordinary avoirdupois ounce. Spot prices are always per troy ounce.
Baby weights in English-speaking hospitals are given as pounds and ounces: 7 lb 8 oz is 7.5 lb, or 3.4 kg.
In the UK and Ireland body weight is spoken in stones and pounds. Eleven stone four is 158 lb, or 71.7 kg.

Sixteen to one, and where that comes from

The avoirdupois system, which is what everyday American and British weights use, divides the pound into sixteen ounces. Sixteen is not arbitrary — it halves cleanly four times, which mattered when merchants divided goods with balance scales rather than arithmetic. Since the international agreement of 1959, the pound has been defined as exactly 0.45359237 kilograms, which makes the ounce exactly 28.349523125 grams. Both figures are definitions rather than measurements, so ounce-to-gram conversions carry no rounding error at all until you decide to round them yourself.

The troy ounce is a different ounce

Gold, silver, platinum and palladium are weighed in troy ounces, a survivor of the medieval Troyes fair system: 31.1034768 grams, about 10% heavier than the avoirdupois ounce used for groceries. The troy pound is stranger still, containing twelve troy ounces rather than sixteen, so a troy pound is actually lighter than an ordinary pound. Every quoted gold price is per troy ounce, which means treating a bullion quote as if it were an ordinary ounce understates the metal by nearly a tenth — a difference of hundreds on a single coin.

Ounces of weight against ounces of volume

A US fluid ounce is 29.5735 millilitres of volume; an ounce is 28.3495 grams of mass. Different quantities entirely.
They coincide only for water, and only roughly, which is where the confusion started.
8 fl oz of honey weighs about 12 oz, because honey is around 1.4 times as dense as water.
American recipes that say "8 oz chocolate" mean weight; ones that say "8 oz milk" mean volume. Context is the only guide.
The imperial fluid ounce used in the UK is 28.4131 ml, slightly different again from the US one.
Nutrition labels use grams for weight and millilitres for volume precisely to avoid this ambiguity.

Where ounces and pounds still rule

Groceries in the United States: deli meat, cheese and produce are priced per pound.
Newborn weight in the US, UK and Ireland, always as pounds and ounces.
Postage: American mail rates step at 1 oz increments for letters and 1 lb for parcels.
Boxing and wrestling weight classes, quoted in pounds worldwide.
Coffee is usually sold in 12 oz or 16 oz bags in the US, against 250 g or 1 kg in Europe.
Precious metals and gemstones use their own units: troy ounces and carats respectively.

Worked examples

Groceries, babies and bullion

A baby weighs 7 lb 8 oz

8 oz ÷ 16 = 0.5 lb
7 + 0.5 = 7.5 lb
7.5 × 0.45359237 = 3.40 kg

7 lb 8 oz = 7.5 lb = 3.40 kg

A recipe calls for 12 oz of flour

12 ÷ 16 = 0.75 lb
12 × 28.3495 = 340 g
That is weight, not a cup measure

12 oz = 0.75 lb = 340 g

Frequently Asked Questions

How many ounces are in a pound?

Sixteen, in the avoirdupois system used for everyday weights. So 8 oz is half a pound and 24 oz is a pound and a half. The troy pound used for precious metals is the exception: it contains twelve troy ounces.

How many grams is an ounce?

28.349523125 grams exactly, because the pound is defined as exactly 0.45359237 kg and the ounce is one sixteenth of it. A pound is therefore 453.592 g, and 2.2 pounds make a kilogram.

Is a fluid ounce the same as an ounce?

No. A fluid ounce measures volume — 29.5735 ml in the US, 28.4131 ml in the UK — while an ounce measures mass. They roughly coincide for water and diverge for everything else: eight fluid ounces of honey weigh about twelve ounces.

Why is a gold ounce heavier than a normal ounce?

Because precious metals use the troy ounce, 31.1035 grams, rather than the avoirdupois ounce of 28.3495 grams. Troy weights come from a separate medieval system that survived only in bullion and gemstones. Every gold spot price is quoted per troy ounce, so the 10% difference is real money.

How do I convert pounds and ounces to kilograms?

Turn the ounces into a fraction of a pound by dividing by 16, add it to the pounds, then multiply by 0.45359237. So 7 lb 8 oz becomes 7.5 lb, which is 3.40 kg. Halving the pounds and taking off a tenth gets you close in your head.

What is a stone in pounds?

Fourteen pounds, which is 6.35 kg. It is still the everyday unit for body weight in the United Kingdom and Ireland, where someone would say eleven stone four rather than 158 pounds. It is almost unknown in the United States, where the same weight is simply 158 lb.