Baby size by week
How long your baby is and how much they weigh in each week of pregnancy, from week 4 to 40, with the fruit that matches their size. Tap a week to see the full development guide.
| Week | Length | Weight | Size of a |
|---|---|---|---|
| Week 4 | 0.1 in (0.1 cm) | — | chia seed |
| Week 5 | 0.1 in (0.2 cm) | — | sesame seed |
| Week 6 | 0.2 in (0.5 cm) | — | pea |
| Week 7 | 0.4 in (0.9 cm) | — | blueberry |
| Week 8 | 0.6 in (1.6 cm) | — | raspberry |
| Week 9 | 0.9 in (2.3 cm) | — | cherry |
| Week 10 | 1.2 in (3.1 cm) | 1.2 oz (35 g) | strawberry |
| Week 11 | 1.6 in (4.1 cm) | 1.6 oz (45 g) | fig |
| Week 12 | 2.1 in (5.4 cm) | 2.0 oz (58 g) | plum |
| Week 13 | 2.6 in (6.7 cm) | 2.6 oz (73 g) | lemon |
| Week 14 | 5.8 in (14.7 cm) | 3.3 oz (93 g) | peach |
| Week 15 | 6.6 in (16.7 cm) | 4.1 oz (117 g) | apple |
| Week 16 | 7.3 in (18.6 cm) | 5.2 oz (146 g) | avocado |
| Week 17 | 8.0 in (20.4 cm) | 6.4 oz (181 g) | pomegranate |
| Week 18 | 8.7 in (22.2 cm) | 7.9 oz (223 g) | bell pepper |
| Week 19 | 9.4 in (24.0 cm) | 9.6 oz (273 g) | mango |
| Week 20 | 10.1 in (25.7 cm) | 11.7 oz (331 g) | banana |
| Week 21 | 10.8 in (27.4 cm) | 14.1 oz (399 g) | baking potato |
| Week 22 | 11.4 in (29.0 cm) | 16.9 oz (478 g) | ear of corn |
| Week 23 | 12.0 in (30.6 cm) | 20.0 oz (568 g) | grapefruit |
| Week 24 | 12.7 in (32.2 cm) | 23.6 oz (670 g) | eggplant |
| Week 25 | 13.3 in (33.7 cm) | 27.7 oz (785 g) | bunch of grapes |
| Week 26 | 13.8 in (35.1 cm) | 32.2 oz (913 g) | turnip |
| Week 27 | 14.4 in (36.6 cm) | 2.3 lb (1,060 g) | cauliflower |
| Week 28 | 14.9 in (37.9 cm) | 2.7 lb (1,210 g) | coconut |
| Week 29 | 15.4 in (39.2 cm) | 3.0 lb (1,370 g) | butternut squash |
| Week 30 | 15.9 in (40.5 cm) | 3.4 lb (1,550 g) | sweetheart cabbage |
| Week 31 | 16.5 in (41.8 cm) | 3.9 lb (1,750 g) | zucchini |
| Week 32 | 16.9 in (43.0 cm) | 4.3 lb (1,950 g) | bunch of celery |
| Week 33 | 17.3 in (44.0 cm) | 4.8 lb (2,160 g) | pineapple |
| Week 34 | 17.8 in (45.2 cm) | 5.2 lb (2,370 g) | cantaloupe melon |
| Week 35 | 18.2 in (46.3 cm) | 5.7 lb (2,590 g) | honeydew melon |
| Week 36 | 18.6 in (47.3 cm) | 6.2 lb (2,810 g) | savoy cabbage |
| Week 37 | 19.0 in (48.3 cm) | 6.7 lb (3,020 g) | leek |
| Week 38 | 19.4 in (49.2 cm) | 7.1 lb (3,230 g) | papaya |
| Week 39 | 19.7 in (50.1 cm) | 7.6 lb (3,430 g) | summer squash |
| Week 40 | 20.1 in (51.0 cm) | 8.0 lb (3,610 g) | pumpkin |
* Until week 13, length is measured from the top of the head to the bottom; from week 14, from head to heel. That's why the number jumps between weeks 13 and 14.
These are averages. Every baby has their own growth curve, and your ultrasound, read by your prenatal care team, is what tells you how your baby is growing.
Frequently Asked Questions
How big is the baby at 22 weeks?
At 22 weeks, the baby measures about 11.4 in (29.0 cm) and weighs around 16.9 oz (478 g).
How much does a baby weigh at 31 weeks?
At 31 weeks, the baby measures about 16.5 in (41.8 cm) and weighs around 3.9 lb (1,750 g).
Why does the baby's length jump at 14 weeks?
Until week 13 the baby is curled up, so the measurement is from the top of the head to the bottom (crown-rump length). From week 14, charts measure from head to heel. The baby doesn't double in size in a week: the ruler changes.
At how many weeks does the baby weigh 1 kg (2.2 lb)?
On average around week 27, early in the third trimester. Weight gain speeds up from there: babies are typically close to 3.5 kg (7.7 lb) by week 40.
Is my baby's size normal?
The numbers in this chart are averages. Every baby follows their own curve, and being a few weeks ahead or behind is usually normal. Your ultrasound, read by your OB or midwife, is what tells you whether your baby is growing well.
14-day free trial
All 40 weeks live in the app
Get your week as it happens — milestones, the checklist, and your baby’s letter.
