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Fetal Weight Chart in Grams

Fetal Weight Chart in Grams

Max Lab

Feb 13, 2023

As an expecting parent, one of the things you’ll want to keep track of is your baby’s growth. By tracking your baby’s weight over time, you can get a better sense of their development and how they’re growing. While there are many different scales available to monitor this, one of the most common ways to measure a baby’s weight is with a fetal weight chart in grams. In this blog post, we will discuss what a fetal weight chart in grams is, why it’s important, and why it may be beneficial to use one when tracking your baby’s growth. We will also provide some tips on how to read and interpret the fetal weight chart in grams so that you have all the information you need to make sure your little one is healthy and happy.

How to read a Fetal Weight Chart

When you are trying to determine the weight of your baby, you will need to use a fetal weight chart. This chart can be found online or in most pregnancy books. To read the chart, you will need to know the date of your last menstrual period (LMP) and your current gestational age.

Once you have this information, locate your LMP on the left side of the chart and find your gestational age along the top. Then, follow these two lines until they intersect on the chart. The number where they meet is your baby's estimated weight in grams.

Keep in mind that this is just an estimate. Your baby may be larger or smaller than the estimate depending on a variety of factors. If you are concerned about your baby's size, talk to your doctor or midwife.

What is the Average Fetal Weight by week?

The average fetal weight by week can vary depending on a number of factors. However, according to the website Kids Health, the average weight of a full-term baby is about 3.2 kg. 

Premature babies tend to weigh less than full-term babies, and they may also have a lower birth weight. For example, a premature baby born at 34 weeks may only weigh 1.8 to 2.3 kg. 

There are many different charts that show the average fetal weights by week, but it's important to remember that every baby is different and will grow at their own pace. If you're concerned about your baby's growth, talk to your healthcare provider.

Gestational age Length (inches) Weight (in Kg) Length (cm) Mass (g)
  (head to bottom) (head to bottom)
8 weeks 0.62 inches 0.020 1.57 cm 20 grams
9 weeks 0.91 inches 0.027 2.30 cm 27 grams
10 weeks 1.22 inch 0.035 3.1 cm 35 grams
11 weeks 1.61 inch 0.045 4.1 cm 45 grams
12 weeks 2.13 inches 0.058 5.4 cm 58 grams
13 weeks 2.64 inches 0.073 6.7 cm 73 grams
  (head to toe) (head to toe)
14 weeks 5.79 inches 0.093 14.7cm 93 grams
15 weeks 6.57 inches 0.117 16.7 cm 117 grams
16 weeks 7.32 inches 0.146 18.6 cm 146 grams
17 weeks 8.03 inches 0.181 20.4 cm 181 grams
18 weeks 8.74 inches 0.223 22.2 cm 223 grams
19 weeks 9.45 inches 0.273 24.0 cm 273 grams
20 weeks 10.12 inches 0.331 25.7 cm 331 grams
21 weeks 10.79 inches 0.399 27.4 cm 399 grams
22 weeks 11.42 inches 0.476 29.0 cm 478 grams
23 weeks 12.05 inches 0.567 30.6 cm 568 grams
24 weeks 12.68 inches 0.671 32.2 cm 670 grams
25 weeks 13.27 inches 0.785 33.7 cm 785 grams
26 weeks 13.82 inches 0.912 35.1 cm 913 grams
27 weeks 14.41 inches 1.057 36.6 cm 1055 grams
28 weeks 14.80 inches 1.211 37.6 cm 1210 grams
29 weeks 15.47 inches 1.379 39.3 cm 1379 grams
30 weeks 15.95 inches 1.560 40.5 cm 1559 grams
31 weeks 16.46 inches 1.751 41.8 cm 1751 grams
32 weeks 16.93 inches 1.950 43.0 cm 1953 grams
33 weeks 17.36 inches 2.164 44.1 cm 2162 grams
34 weeks 17.84 inches 2.377 45.3 cm 2377 grams
35 weeks 18.23 inches 2.595 46.3 cm 2595 grams
36 weeks 18.62 inches 2.812 47.3 cm 2813 grams
37 weeks 19.02 inches 3.030 48.3 cm 3028 grams
38 weeks 19.41 inches 3.234 49.3 cm 3236 grams
39 weeks 19.72 inches 3.434 50.1 cm 3435 grams
40 weeks 20.08 inches 3.620 51.0 cm 3619 grams
41 weeks 20.39 inches 3.787 51.8 cm 3787 grams

How to use a fetal weight chart to predict your baby's birth weight

A fetal weight chart is a tool that can be used to predict your baby's birth weight. This can be helpful information for you and your healthcare provider. To use a fetal weight chart, you will need to know the date of your last menstrual period (LMP) and the number of weeks pregnant you are. Once you have this information, you can find your baby's estimated weight on the chart.

If you are unsure of your LMP or how many weeks pregnant you are, your healthcare provider can help you determine this information. It is important to note that the fetal weight chart is only an estimate. Your baby may weigh more or less than what is predicted on the chart.

If you have any concerns about your baby's growth, be sure to discuss them with your healthcare provider.


Fetal weight charts in grams can be a useful tool for assessing the health of your baby and tracking its growth throughout pregnancy. While these charts may not always provide an exact measurement, they are still helpful in determining whether or not your baby is growing at a healthy rate. Many hospitals will use this chart to monitor fetal development during check-ups, but you can also refer to it when you have any questions about the size and weight of your baby.


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