Baby Size by Week Calculator
See your baby’s typical length, weight and fruit-sized comparison for any pregnancy week from 4 to 40.
How it works
Median fetal length and weight by gestational week (Hadlock-based growth references)
Length is measured crown-to-rump until about week 20, when the legs uncurl and head-to-heel becomes standard — which is why the number jumps there. Weight gain accelerates in the third trimester, from about 600 g at 24 weeks to 3.4 kg at term. Individual babies vary widely; scans track your baby’s own curve.
Worked example
Week 24: about 30 cm long and 600 g — the size of an ear of corn.
Frequently asked questions
Are these exact?
No — they are population medians. A healthy baby can be well above or below them; percentile is what your sonographer tracks.
Why do sites disagree on the fruit?
Fruit comparisons are informal. The length and weight figures matter more.
Related calculators
Educational estimate only — your midwife or doctor will confirm dates and advice for your pregnancy.