How to Convert Pounds to Ounces

Standard Conversions

Write the number of pounds. If you are converting the weight of a real-life object, you can use a scale to weigh it. If you already know the weight in pounds, just write the number and label it "lbs". Let's follow along with an example. Say that a newborn baby is weighed at the doctor's office and found to be exactly 10 pounds. We would start our conversion by writing 10 lbs on the paper.

Multiply by 16. This is the number of ounces in one pound. In our example, we would multiply 10 × 16 to get 160.

Don't forget the "ounces" label. Writing "ounces" or "oz" next to your answer is important. If you don't, it won't be clear which units you converted to. If you're doing this work for school, you may even lose points for forgetting to label. In our example, we would write our answer as either "160 ounces" or "160 oz." Both mean the same thing.

Convert back to pounds by dividing by 16. Division is basically the "opposite" of multiplication. This means that dividing by the same number that you multiply by will "undo" your work. In other words, dividing a number of ounces by 16 will get you an answer in pounds. In our example, dividing the baby's weight in ounces by 16 gets us 160/16 = 10 lbs. Don't forget the "pounds" label.

Dealing With Non-Standard Ounces

Don't confuse fluid ounces with ordinary ounces. "Fluid ounces" (fl oz) are used for volume, or the space something takes up. They are usually used for liquids (like water, milk, juice, etc.). Fluid ounces do not tell an object's weight. This means that 16 fl oz of a certain liquid doesn't necessarily weigh 1 lb. As an example, one fluid ounce of honey weighs about 1 1/2 ounces. This means that 16 fl oz weighs about 24 ounces, or a pound and a half.

Use troy ounces for precious metals. Troy ounces, which are used to weigh precious metals like gold and silver, are a little heavier than ordinary ounces. There are about 14.6 troy ounces in a pound. This means that to convert a pound to troy ounces, you can multiply by 14.6. For example, let's say that an old, heavy gold necklace is weighed at exactly half a pound. We can convert to troy ounces by multiplying 0.5 × 14.6 = 7.3 troy ounces.

Convert between oz/square inch and lbs/square inch as normal. "Ounces per square inch" are used to measure pressure and surface density (thickness) of thin materials like paper. There are 16 oz/square inch in one lb/square inch, so you can convert by multiplying by 16 just like with normal ounces and pounds. This is also true for ounces and pounds per cubic inch — just multiply by 16 like normal.