fetal weight at 21 weeks in grams?

Growth chart: Fetal length and weight, week by week
Find out how big your baby is during each week of their development with our fetal growth chart. From early in pregnancy, babies grow at different rates, so these numbers are merely averages. Your baby's actual size by week (in length and weight) may vary substantially.
pregnant woman with a laptop looking at a ultrasound photo
How big is my baby?

Wondering how big your baby is during each week of pregnancy? The numbers in our chart below can give you a sense of your baby's size. Keep in mind that your baby may be much smaller or larger than these averages. That's okay – after all, healthy babies can weigh less than 5 pounds or more than 9 pounds at birth.

Boy's measurements are different than girl's measurements, even this early. For the numbers on our chart, we've taken an average of boys and girls.

Another thing to note: Until 14 weeks, a baby's length measurement is given from crown to rump (bottom). After 14 weeks, the measurement given is from crown to heel.

If you're curious, see our pregnancy timing article to learn how the weeks of pregnancy are counted. And if you don't know your due date, use our due date calculator to find out.
Inside pregnancy: Weeks 1 to 9
1:57 min
In early pregnancy your baby grows dramatically, from a tiny dot to the size of a grape.
Fetal growth chart
Gestational age Length (US) Weight (US) Length (cm) Mass (g)
(crown to rump) (crown to rump)
10 weeks 1.22 inch 1.23 ounces 3.1 cm 35 grams
11 weeks 1.61 inch 1.59 ounces 4.1 cm 45 grams
12 weeks 2.13 inches 2.05 ounces 5.4 cm 58 grams
13 weeks 2.64 inches 2.58 ounces 6.7 cm 73 grams
(crown to heel) (crown to heel)
14 weeks 5.79 inches 3.28 ounces 14.7cm 93 grams
15 weeks 6.57 inches 4.13 ounces 16.7 cm 117 grams
16 weeks 7.32 inches 5.15 ounces 18.6 cm 146 grams
17 weeks 8.03 inches 6.38 ounces 20.4 cm 181 grams
18 weeks 8.74 inches 7.87 ounces 22.2 cm 223 grams
19 weeks 9.45 inches 9.63 ounces 24.0 cm 273 grams
20 weeks 10.12 inches 11.68 ounces 25.7 cm 331 grams
21 weeks 10.79 inches 14.07 ounces 27.4 cm 399 grams
22 weeks 11.42 inches 1.05 pounds 29.0 cm 478 grams
23 weeks 12.05 inches 1.25 pounds 30.6 cm 568 grams
24 weeks 12.68 inches 1.48 pounds 32.2 cm 670 grams
25 weeks 13.27 inches 1.73 pounds 33.7 cm 785 grams
26 weeks 13.82 inches 2.01 pounds 35.1 cm 913 grams
27 weeks 14.41 inches 2.33 pounds 36.6 cm 1055 grams
28 weeks 14.80 inches 2.67 pounds 37.6 cm 1210 grams
29 weeks 15.47 inches 3.04 pounds 39.3 cm 1379 grams
30 weeks 15.95 inches 3.44 pounds 40.5 cm 1559 grams
31 weeks 16.46 inches 3.86 pounds 41.8 cm 1751 grams
32 weeks 16.93 inches 4.31 pounds 43.0 cm 1702 grams
33 weeks 17.36 inches 4.77 pounds 44.1 cm 1953 grams
34 weeks 17.84 inches 5.24 pounds 45.3 cm 2377 grams
35 weeks 18.23 inches 5.72 pounds 46.3 cm 2595 grams
36 weeks 18.62 inches 6.20 pounds 47.3 cm 2813 grams
37 weeks 19.02 inches 6.68 pounds 48.3 cm 3028 grams
38 weeks 19.41 inches 7.13 pounds 49.3 cm 3236 grams
39 weeks 19.72 inches 7.57 pounds 50.1 cm 3435 grams
40 weeks 20.08 inches 7.98 pounds 51.0 cm 3619 grams
41 weeks 20.39 inches 8.35 pounds 51.8 cm 3787 grams

Thanks to Dr. Mark Curran, maternal-fetal medicine specialist, for his help in preparation of this table.

Where to go next:

See the ultimate pregnancy to-do list for the first, second, and third trimesters
Use our Baby Names Finder
Video: Watch how your body changes to make room for your growing baby