A pound is a customary and imperial unit commonly used for body weight, packages, shipping, groceries, gym weights, tools, and product labels in the United States. In everyday conversion, pound usually means pound-mass.
Quick facts
- Unit name
- pound
- Plural
- pounds
- Symbol
- lb
- Quantity
- mass in everyday conversion
- System
- US customary and imperial
- Kilogram relation
- 1 lb = 0.45359237 kg
- Ounce relation
- 1 lb = 16 oz
- Stone relation
- 14 lb = 1 st
Visual scale
One pound is less than half a kilogram. It is a practical small-to-medium everyday weight unit.
Definition and exact value
The international avoirdupois pound is defined exactly as 0.45359237 kilograms. This exact relationship is the basis for pound-to-kilogram and kilogram-to-pound conversion.
Symbol and writing rules
The common symbol for pound is lb. The plural is written the same way as a symbol, so use 1 lb and 12 lb. In prose, write "1 pound" and "12 pounds".
Pound-mass vs pound-force
The word pound can refer to mass or force depending on context. Everyday body weight, shipping weight, food labels, and converter pages usually use pound as pound-mass. Pound-force is a force unit and belongs in force calculations, not ordinary mass conversion.
How heavy is one pound?
One pound is useful for small packages, food portions, gym plates, tools, and consumer goods. It is larger than an ounce and smaller than a kilogram.
Everyday scale
Many packaged foods and household items weigh around a fraction of a pound to several pounds.
Body scale
Human body weight in the United States is commonly expressed in pounds.
Shipping scale
Parcel weights and carrier rules in the US often use pounds and ounces.
Pound vs kilogram
The pound is customary; the kilogram is SI and metric. One kilogram equals about 2.2046226218 pounds, and one pound equals exactly 0.45359237 kilograms.
Pound vs ounce
Ounces are used for smaller weights. One pound equals exactly 16 ounces. Use ounces for small package weights, food portions, and postal details; use pounds for larger everyday weights.
| Unit | Relationship | Typical use |
|---|---|---|
| ounce | 1 oz = 1/16 lb | small goods, food, postal weight |
| pound | 1 lb = 16 oz | body weight, parcels, gym weights |
| stone | 1 st = 14 lb | body weight in some UK contexts |
Common uses
- Body weight and fitness tracking in US customary contexts.
- Shipping, parcel weights, luggage limits, and carrier rules.
- Food labels, grocery items, meat, produce, and household goods.
- Gym weights, dumbbells, plates, tools, and product specifications.
How pounds are measured
Pounds are measured with scales. Bathroom scales, postal scales, kitchen scales, luggage scales, and industrial scales may show pounds, ounces, kilograms, or multiple units.
- Use a scale with enough capacity for the item.
- Tare containers when only the contents should be measured.
- Record pounds and ounces carefully when the scale does not show decimal pounds.
Precision and rounding
For body weight, one decimal place may be enough. For shipping and commercial labeling, follow the precision required by the carrier, label, or regulation. Avoid rounding before converting to kilograms.
Conversion formulas
Pound conversion table
| Pounds | Kilograms | Ounces | Grams | Stone |
|---|---|---|---|---|
| 1 lb | 0.45359237 kg | 16 oz | 453.59237 g | 0.0714285714 st |
| 5 lb | 2.26796185 kg | 80 oz | 2,267.96185 g | 0.3571428571 st |
| 10 lb | 4.5359237 kg | 160 oz | 4,535.9237 g | 0.7142857143 st |
| 100 lb | 45.359237 kg | 1,600 oz | 45,359.237 g | 7.142857143 st |
Common mistakes
- Using lb as a plural word: write 12 lb as a symbol, not 12 lbs in strict technical style.
- Confusing ounces of weight with fluid ounces: oz measures weight or mass; fl oz measures volume.
- Using 2.2 as exact: one kilogram is about 2.2046226218 pounds.
- Confusing pound-mass and pound-force: they are different in technical calculations.
- Rounding shipping weights too early: carrier billing can depend on rounding rules.
Related Xunits pages
Pound converters
Weight references
FAQ
How many kilograms are in one pound?
One pound equals exactly 0.45359237 kilograms.
How many ounces are in one pound?
One pound equals exactly 16 ounces.
What is the symbol for pound?
The common symbol is lb.
Is pound a mass or weight unit?
In everyday conversion, pound usually means pound-mass. In technical force contexts, pound-force is a separate force unit.
Is lb the same as lbs?
lb is the standard unit symbol. lbs is common informal plural writing, but technical unit symbols are not pluralized.
Is 1 pound exactly 0.45 kg?
No. 0.45 kg is a rough estimate. The exact relationship is 1 lb = 0.45359237 kg.
Reference notes
This guide uses the exact international avoirdupois pound relationship of 1 lb = 0.45359237 kg and the exact ounce relationship of 1 lb = 16 oz.