Your baby is constantly growing and developing throughout your pregnancy. This chart will give you a general idea of how big your baby is at different stages during your pregnancy.
This chart is for information purposes only. Your midwife will give you the most accurate measurement of your baby. There are two ways to measure the size of your baby:
- By measuring the size of your bump, this is known as measuring the fundal height. They will measure from your pubic bone to the top of your uterus, to make sure your baby’s growth is on track for your stage of pregnancy. .
- Your baby’s size can also be measured when you go for an ultrasound scan, such as your 12 week dating scan or a growth scan if your midwife thinks it’s necessary.
If you have any questions about the size of your baby and stage of pregnancy, please speak to your community midwife. We cannot give advice on individual pregnancies, particularly as we do not have access to your maternity notes.
We would love to support you with your antenatal classes though. We have options to suit all budgets and locations UK-wide. Click on the links below for more information:
- Antenatal classes in Bath
- Antenatal classes in Bristol
- Digital antenatal courses
- Free antenatal course
Pregnancy: baby growth chart
| PREGNANCY / WEEK | BABY’S LENGTH / CM | BABY’S WEIGHT / G | BABY’S LENGTH / IN | BABY’S WEIGHT / OZ |
| Week 4 | 0.036 – 0.10 cm | – | up to 0.04 in | < 0.04 oz |
| Week 5 | 0.13 cm | – | 0.05 n | < 0.04 oz |
| Week 6 | 0.32 cm | – | 0.13 in | < 0.04 oz |
| Week 7 | 1.27 cm | – | 0.5 in | < 0.04 oz |
| From 8 – 19 weeks your baby’s measurement is from crown to rump | ||||
| Week 8 | 1.60 cm | 1 g | 0.63 in | 0.04 oz |
| Week 9 | 2.30 cm | 2 g | 1.22 in | 0.07 oz |
| Week 10 | 3.10 cm | 4 g | 1.22 in | 0.14 oz |
| Week 11 | 4.10 cm | 7 g | 1.61 in | 0.25 oz |
| Week 12 | 5.40 cm | 14 g | 2.13 in | 0.49 oz |
| Week 13 | 7.40 cm | 23 g | 2.91 in | 0.81 oz |
| Week 14 | 8.70 cm | 43 g | 3.42 in | 1.52 oz |
| Week 15 | 10.10 cm | 70 g | 3.98 in | 2.47 oz |
| Week 16 | 11.16 cm | 100 g | 4.57 in | 3.53 oz |
| Week 17 | 13.00 cm | 140 g | 5.12 in | 4.94 oz |
| Week 18 | 14.20 cm | 190 g | 5.59 in | 6.70 oz |
| Week 19 | 15.30 cm | 240 g | 6.02 in | 8.47 oz |
| From 20 weeks your baby’s measurement is from crown to heel | ||||
| Week 20 | 25.60 cm | 300 g | 10.08 in | 10.58 oz |
| Week 21 | 26.70 cm | 360 g | 10.51 in | 12.70 oz |
| Week 22 | 27.80 cm | 430 g | 10.94 in | 15.17 oz |
| Week 23 | 28.90 cm | 501 g | 11.38 in | 1.10 lb |
| Week 24 | 30.00 cm | 600 g | 11.81 in | 1.32 lb |
| Week 25 | 34.60 cm | 660 g | 13.62 in | 1.46 lb |
| Week 26 | 35.60 cm | 760 g | 14.02 in | 1.68 lb |
| Week 27 | 36.60 cm | 875 g | 14.41 in | 1.93 lb |
| Week 28 | 37.60 cm | 1005 g | 14.80 in | 2.22 lb |
| Week 29 | 38.60 cm | 1153 g | 15.20 in | 2.54 lb |
| Week 30 | 39.90 cm | 1319 g | 15.71 in | 2.91 lb |
| Week 31 | 41.10 cm | 1502 g | 16.18 in | 3.31 lb |
| Week 32 | 42.40 cm | 1702 g | 16.69 in | 3.75 lb |
| Week 33 | 43.70 cm | 1918 g | 17.20 in | 4.23 lb |
| Week 34 | 45.00 cm | 2146 g | 17.72 in | 4.73 lb |
| Week 35 | 46.20 cm | 2383 g | 18.19 in | 5.25 lb |
| Week 36 | 47.40 cm | 2622 g | 18.66 in | 5.78 lb |
| Week 37 | 48.60 cm | 2859 g | 19.13 in | 6.30 lb |
| Week 38 | 49.80 cm | 3083 g | 19.61 in | 6.80 lb |
| Week 39 | 50.70 cm | 3288 g | 19.96 in | 7.25 lb |
| Week 40 | 51.20 cm | 3462 g | 20.16 in | 7.63 lb |
