Birth Weight Converter
Turn a baby's weight in pounds and ounces into grams and kilograms, or convert grams from a hospital record back into lb and oz. You'll also see the birth weight category (low, normal or high) and a full lb + oz to grams chart.
Last updated:
0–15.9
How to use the Birth Weight Converter
- Choose the direction: lb + oz to metric, or grams / kg to lb + oz.
- Enter the weight, for example 7 lb 8 oz or 3,400 g.
- Press Convert to see every unit and the birth weight category.
- Check the chart to look up other weights quickly.
- Copy the result to share it in a birth announcement or baby book.
Birth weight categories
| Category | Grams | Pounds and ounces |
|---|---|---|
| Extremely low birth weight | under 1,000 g | under 2 lb 3 oz |
| Very low birth weight | 1,000–1,499 g | 2 lb 3 oz – 3 lb 5 oz |
| Low birth weight | 1,500–2,499 g | 3 lb 5 oz – 5 lb 8 oz |
| Normal | 2,500–3,999 g | 5 lb 8 oz – 8 lb 13 oz |
| High (macrosomia) | 4,000 g and over | 8 lb 13 oz and over |
The categories are based on weight alone. Doctors also compare weight with gestational age (small, appropriate or large for gestational age), which needs a growth chart for weeks of pregnancy.
Conversion formulas
- 1 pound (lb) = 16 ounces = 453.59237 grams
- 1 ounce (oz) = 28.349523 grams
- 1 kilogram = 1,000 grams = 2.20462 lb = 35.274 oz
- lb + oz to grams: lb × 453.592 + oz × 28.3495
- grams to lb + oz: total oz = g ÷ 28.3495; lb = whole part of total oz ÷ 16; oz = total oz − lb × 16
Common birth weights
| lb + oz | Grams | kg |
|---|---|---|
| 5 lb 8 oz | 2,495 g | 2.49 kg |
| 6 lb 0 oz | 2,722 g | 2.72 kg |
| 6 lb 8 oz | 2,948 g | 2.95 kg |
| 7 lb 0 oz | 3,175 g | 3.18 kg |
| 7 lb 8 oz | 3,402 g | 3.40 kg |
| 8 lb 0 oz | 3,629 g | 3.63 kg |
| 8 lb 8 oz | 3,856 g | 3.86 kg |
| 9 lb 0 oz | 4,082 g | 4.08 kg |
| 10 lb 0 oz | 4,536 g | 4.54 kg |
Frequently asked questions
How do I convert pounds and ounces to grams?
Multiply the pounds by 453.592 and the ounces by 28.3495, then add them. For example, 7 lb 8 oz = 7 × 453.592 + 8 × 28.3495 = 3,175 + 227 = 3,402 grams (3.4 kg).
How do I convert grams to pounds and ounces?
Divide the grams by 28.3495 to get total ounces, then divide by 16: the whole number is pounds and the remainder is ounces. 3,500 g ÷ 28.3495 = 123.5 oz = 7 lb 11.5 oz.
What is a normal birth weight?
A full-term baby weighing between 2,500 and 3,999 grams (about 5 lb 8 oz to 8 lb 13 oz) is in the normal range. The average newborn in the US weighs about 3.3–3.4 kg (around 7 lb 5 oz).
What counts as low birth weight?
Low birth weight is under 2,500 g (5 lb 8 oz), very low birth weight is under 1,500 g (3 lb 5 oz) and extremely low birth weight is under 1,000 g (2 lb 3 oz). These definitions apply regardless of how many weeks the baby was born at.
What is a high birth weight?
A baby weighing 4,000 g (8 lb 13 oz) or more is often described as large or having macrosomia; some guidelines use 4,500 g (9 lb 15 oz) as the cut-off.
Why do hospitals record weight in grams?
Grams are precise and used for medical calculations and growth charts worldwide, so many hospitals weigh babies in grams and convert to pounds and ounces for parents.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.