How this calculator works
Pounds and ounces belong to the avoirdupois system, in which sixteen ounces make one pound. Entering a weight as 3 pounds 4 ounces is the same as 3 pounds plus 4 ounces, so the page adds the two boxes, then carries any whole group of sixteen ounces into the pounds figure. It also gives the total as a decimal number of pounds and in metric units. The pound here is exactly 0.45359237 kg, so the ounce is exactly 28.349523125 g.
Formula
total ounces = pounds x 16 + ounces. decimal pounds = total ounces / 16. kilograms = total ounces x 0.028349523125. grams = kilograms x 1,000. Whole pounds = floor(total ounces / 16) and remaining ounces = total ounces - 16 x whole pounds.
Worked example
3 lb 4 oz is 52 oz, 3.25 lb, 1.47418 kg and 1,474.18 g. 0 lb 20 oz carries to 1 lb 4 oz, or 1.25 lb. 2 lb 8 oz is 40 oz and 2.5 lb, which is 1.13398 kg.
Advertisement
Frequently asked questions
What happens if I enter more than 16 ounces?
The extra ounces are carried into pounds. For example, 1 lb 20 oz becomes 2 lb 4 oz, because 20 oz is 1 lb 4 oz. The total is unchanged.
Is this a weight or a mass?
Mass. A scale calibrated in pounds reports mass. Physical weight is a force measured in newtons and depends on gravity.
Are these troy pounds or troy ounces?
No. All values here use the avoirdupois pound and ounce used for groceries and postal weights. A troy ounce is exactly 31.1034768 g and a troy pound is twelve troy ounces, a different system.
Why is the kilograms row not a round number?
The pound and kilogram are defined by different standards, so the conversion has an exact but non-round factor. One pound is exactly 0.45359237 kg, which is why 3 lb 4 oz gives 1.47418 kg.