An avoirdupois ounce is 1/16 pound.
Ounces to Pounds Converter — oz to lb
Convert Ounce (oz) to Pound (lb) using the exact conversion factor (1 ounce = 0.0625 pound). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Ounces to Pounds converter
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An avoirdupois pound is exactly 0.45359237 kilograms.
Result = input x 0.02834952313 / 0.45359237.
Mass uses the kilogram as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Ounces to Pounds
Weight conversions between Ounce and Pound come up constantly in everyday commerce, shipping, and cooking, since US packaging is usually labeled in pounds while most of the rest of the world uses kilograms. Ounce is typically associated with united States (cooking, postal, retail), while Pound is typically associated with united States (primary mass/weight unit).
Formula
pounds = ounces × 0.0625
This factor comes from each unit's defined relationship to the category's base unit: 1 ounce equals 0.028349523125 base units, and 1 pound equals 0.45359237 base units, so dividing one by the other gives the direct ounce-to-pound factor of 0.0625.
Simple example
1 oz × 0.0625 = 0.0625 lb
1 ounce = 0.0625 pounds.
Real-world example
50 oz × 0.0625 = 3.125 lb
50 ounces = 3.125 pounds.
Conversion table
| Ounce (oz) | Pound (lb) |
|---|---|
| 1 oz | 0.0625 lb |
| 5 oz | 0.3125 lb |
| 10 oz | 0.625 lb |
| 25 oz | 1.5625 lb |
| 50 oz | 3.125 lb |
| 100 oz | 6.25 lb |
Reverse conversion: Pound to Ounce
0.0625 lb × 16 = 1 oz
0.0625 pounds = 1 ounce.
ounces = pounds × 16
For a page dedicated to this direction, see Pound to Ounce.
Ounce vs. Pound
| Aspect | Ounce | Pound |
|---|---|---|
| Family | US/imperial customary unit | US/imperial customary unit |
| Typical use | US cooking and recipe measurement (small quantities) | Body weight and food retail packaging in the United States |
| Where it's used | United States (cooking, postal, retail) | United States (primary mass/weight unit) |
Understanding the Ounce
Ounce (oz) measures mass. The avoirdupois ounce is 1/16 of a pound: exactly 28.349523125 grams. It is classified as a US/imperial customary unit.
Where it's used: United States (cooking, postal, retail) United Kingdom (informal/retail use)
Avoirdupois ounce vs. troy ounce. The everyday ounce (avoirdupois, 28.35 g) used for cooking and shipping is a different, smaller unit than the troy ounce (31.10 g) used for precious metals like gold and silver — this page uses the everyday avoirdupois ounce.
Uses of the Ounce today
- US cooking and recipe measurement (small quantities)
- US postal and shipping weight
- Precious metals (troy ounce, a related but distinct unit)
History of the Ounce
The ounce descends from the Roman 'uncia' (a twelfth part), inherited through medieval English weight systems; the avoirdupois ounce (for general goods, as opposed to the troy ounce for precious metals) became standard for everyday trade, fixed at exactly 28.349523125 g via the pound's 1959 international standardization.
Historical origin. Ounce was not the invention of a single named person; it developed through the process described above.
Understanding the Pound
Pound (lb) measures mass. The avoirdupois pound is legally defined as exactly 0.45359237 kilograms, fixed by international treaty in 1959. It is classified as a US/imperial customary unit.
Where it's used: United States (primary mass/weight unit) United Kingdom (informal and some retail use) Various Caribbean and Pacific territories with historical UK/US ties
Pound-mass vs. pound-force. This page converts pound-mass (lbm), a unit of mass. Pound-force (lbf) is a separate unit measuring the force gravity exerts on one pound-mass, used in engineering contexts like pounds per square inch.
Uses of the Pound today
- Body weight and food retail packaging in the United States
- Postal, parcel, and freight weight in US shipping and logistics
- Pound-force (lbf) and its derivatives (psi, foot-pounds) in US engineering and aerospace
History of the Pound
Unlike the kilogram's single documented birth in revolutionary France, the pound's history is a long, layered narrowing of competing regional standards. The avoirdupois pound — ancestor of today's standard — emerged among London merchants in the early 14th century (recorded use around 1303), used for weighing wool and other bulk goods under the system merchants called 'avoir de pois,' Old French for 'goods of weight.' Its 16-ounce structure suited large-scale trade better than the 12-ounce troy pound used for precious metals.
Wool merchants used a related 'wool pound' of about 6,992 grains — close enough to 7,000 that Elizabeth I's government formally fixed the avoirdupois pound at exactly 7,000 grains in 1588, the value still used today. Britain and the US then refined their physical standards separately over the following centuries, leaving small discrepancies between them.
Those discrepancies were resolved on 1 July 1959, when the US, UK, Canada, Australia, New Zealand, and South Africa signed the International Yard and Pound Agreement, fixing the pound at exactly 0.45359237 kg and the yard at exactly 0.9144 m. The US National Bureau of Standards (now NIST) adopted the value immediately; the UK followed via its Weights and Measures Act 1963 — the value used by virtually every country today.
Historical origin. Pound was not the invention of a single named person; it developed through the process described above.
Ounce — sources
- NIST — International yard and pound (1959) — Basis for the modern ounce via the standardized pound.
Pound — sources
- NIST — International yard and pound, Federal Register notice (1959) — Official 1959 refinement of the yard and pound values adopted by the US National Bureau of Standards.
- Encyclopaedia Britannica — 'Pound (unit of weight)' — History of the Tower, troy, and avoirdupois pounds and their standardization in England.
- UK Weights and Measures Act 1963, s.1(1) — Statutory UK definition of the pound as exactly 0.45359237 kilogram.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many pounds are in 1 ounce?
1 ounce equals 0.0625 pounds, using the exact defined conversion factor rather than an estimate.
How do I convert ounce to pound?
Multiply the ounce value by 0.0625. The converter above does this instantly to whatever precision you set.
How do I convert pound back to ounce?
Use the reverse factor: 1 pound equals 16 ounces. You can also use the swap control in the converter above to flip the direction instantly.
What is a ounce?
Ounce (oz) measures mass. The avoirdupois ounce is 1/16 of a pound: exactly 28.349523125 grams. It is classified as a US/imperial customary unit.
What is a pound?
Pound (lb) measures mass. The avoirdupois pound is legally defined as exactly 0.45359237 kilograms, fixed by international treaty in 1959. It is classified as a US/imperial customary unit.
Is the ounce to pound conversion exact?
Yes. The avoirdupois pound is legally defined as exactly 0.45359237 kilograms, fixed by international treaty in 1959. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
What is the difference between avoirdupois ounce vs. troy ounce?
The everyday ounce (avoirdupois, 28.35 g) used for cooking and shipping is a different, smaller unit than the troy ounce (31.10 g) used for precious metals like gold and silver — this page uses the everyday avoirdupois ounce.
Where is the ounce still used today?
United States (cooking, postal, retail) United Kingdom (informal/retail use)