Pounds and Ounces to Kilograms Calculator
lb
oz
Kilograms:
Grams:
Pounds (decimal):
Calculation:
This calculator converts a weight in pounds and ounces to kilograms and grams. It is the format used for newborn birth weights in the US and on many packages and shipping labels.
Below you will find the exact formula, worked examples and a chart of typical birth weights.
How to use the pounds and ounces to kilograms calculator?
Step 1: Type the pounds in the first box and the ounces in the second. If the weight has no ounces, leave that box empty or enter 0.
Step 2: Click Convert or press Enter.
Step 3: The weight in kilograms appears on the right. Below it you get the grams and the weight in decimal pounds.
Step 4: The Calculation box shows how the ounces are added up and turned into grams.
Pounds and ounces to kilograms formula
A pound has 16 ounces, and one ounce of weight is exactly 28.349523125 grams. First turn everything into ounces, then into grams:
| m(g) = (m(lb) × 16 + m(oz)) × 28.349523125 |
To get kilograms, divide the grams by 1000. The ounces can have decimals and can also be 16 or more: the calculator adds them up all the same.
Pounds and ounces to kilograms examples
Example 1: A newborn who weighs 7 pounds 8 ounces
Turn everything into ounces:
7 × 16 + 8 = 120 oz
Convert the ounces to grams, then the grams to kilograms:
120 × 28.349523125 ≈ 3401.94 g
3401.94 g ÷ 1000 ≈ 3.402 kg
A baby who weighs 7 lb 8 oz weighs about 3402 grams, which is 3.402 kg.
Example 2: Convert 6 pounds 4 ounces to kilograms
6 × 16 + 4 = 100 oz
100 × 28.349523125 ≈ 2834.95 g
2834.95 g ÷ 1000 ≈ 2.835 kg
Example 3: A package that weighs 2 pounds 12 ounces
2 × 16 + 12 = 44 oz
44 × 28.349523125 ≈ 1247.38 g
1247.38 g ÷ 1000 ≈ 1.247 kg
Example 4: Ounces only, a 12 oz bag of coffee
If the weight is only in ounces, leave the pounds empty or at 0:
12 × 28.349523125 ≈ 340.19 g
That is 0.3402 kg.
Pounds and ounces to kilograms chart (birth weights)
| Pounds and ounces | Kilograms (kg) | Grams (g) |
|---|---|---|
| 5 lb 0 oz | 2.268 kg | 2268 g |
| 5 lb 8 oz | 2.495 kg | 2495 g |
| 6 lb 0 oz | 2.722 kg | 2722 g |
| 6 lb 4 oz | 2.835 kg | 2835 g |
| 6 lb 8 oz | 2.948 kg | 2948 g |
| 6 lb 12 oz | 3.062 kg | 3062 g |
| 7 lb 0 oz | 3.175 kg | 3175 g |
| 7 lb 4 oz | 3.289 kg | 3289 g |
| 7 lb 8 oz | 3.402 kg | 3402 g |
| 7 lb 12 oz | 3.515 kg | 3515 g |
| 8 lb 0 oz | 3.629 kg | 3629 g |
| 8 lb 4 oz | 3.742 kg | 3742 g |
| 8 lb 8 oz | 3.856 kg | 3856 g |
| 8 lb 12 oz | 3.969 kg | 3969 g |
| 9 lb 0 oz | 4.082 kg | 4082 g |
| 9 lb 8 oz | 4.309 kg | 4309 g |
| 10 lb 0 oz | 4.536 kg | 4536 g |
Frequently asked questions
How many grams are in an ounce?
One ounce of weight is 28.35 g. The exact value is 28.349523125 g.
How many ounces are in a pound?
A pound has 16 ounces. So 8 ounces is half a pound, and 7 lb 8 oz is the same as 7.5 lb.
How many kilograms is an 8 pound baby?
8 pounds is 3.629 kg (3629 g). At 8 pounds 4 ounces the weight is 3.742 kg.
Is a weight ounce the same as a fluid ounce?
No. The ounce on this page measures weight (mass). A fluid ounce measures volume, as on bottles and drinks, and a US fluid ounce is about 29.57 mL. See the ounces to milliliters calculator for that one.
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