Kilograms to pounds and ounces, and back.
A free baby weight converter, plus centimeters to inches for her length. Type in either box and the other follows. No account, and nothing you type gets sent anywhere.
Convert a weight or a length
1 kg is 2.20462 lb and 1 cm is 0.393701 in. Ounces round to the nearest whole ounce.
Common baby weights in pounds and ounces
| Kilograms | Pounds and ounces |
|---|---|
| 2.5 kg | 5 lb 8 oz |
| 3 kg | 6 lb 10 oz |
| 3.2 kg | 7 lb 1 oz |
| 3.5 kg | 7 lb 11 oz |
| 4 kg | 8 lb 13 oz |
| 4.5 kg | 9 lb 15 oz |
| 5 kg | 11 lb 0 oz |
| 6 kg | 13 lb 4 oz |
| 7 kg | 15 lb 7 oz |
| 8 kg | 17 lb 10 oz |
| 9 kg | 19 lb 13 oz |
| 10 kg | 22 lb 1 oz |
| 12 kg | 26 lb 7 oz |
Common baby lengths in centimeters and inches
| Centimeters | Inches |
|---|---|
| 45 cm | 17.7 in |
| 48 cm | 18.9 in |
| 50 cm | 19.7 in |
| 52 cm | 20.5 in |
| 55 cm | 21.7 in |
| 60 cm | 23.6 in |
| 65 cm | 25.6 in |
| 70 cm | 27.6 in |
| 75 cm | 29.5 in |
| 80 cm | 31.5 in |
| 90 cm | 35.4 in |
| 100 cm | 39.4 in |
Why does a baby's weight come in pounds and ounces?
Because a baby’s weight needs small steps. A newborn weighs around 3.3 kg, and one decimal place of a kilogram is 100 g, about a wet diaper. Ounces cut the same range into 28 g steps, no decimal point needed.
US hospitals announce births in pounds and ounces. Almost everywhere else uses kilograms, and the WHO growth charts are in kilograms and centimeters. So plenty of parents end up juggling both, especially families spread across countries.
Convert kilograms to pounds and ounces and back again, and you might land a few grams from where you started. That’s the ounce rounding: whole ounces sit about 28 g apart. Pounds and ounces to kilograms and back is exact.
You in kilograms, your partner in pounds? In Bundle of Joy each of you picks your own units, and the same weigh-in reads right on both phones, growth chart included.
The other free tools
- WHO growth chart calculator. Plot a measurement and get the percentile, in either unit.
- Baby age calculator. Days, weeks, months and corrected age.
- Diaper size calculator. Which sizes fit a given weight.
- The WHO weight tables. Every month from birth to five years, in both units.
Every weigh-in, on both your phones.
Weight, height and head circumference on the WHO charts, shared with your partner.
