Baby Weight Gain Rate Calculator
Reviewed by Hamza Gujjar, Algorithm Architect & Software Developer
Last updated: July 27, 2026
Disclaimer: This calculator is provided for informational and educational purposes only and does not constitute financial, medical, legal, or other professional advice. Always consult a qualified professional before making decisions based on these results.
Turning two weigh-ins into a growth trend
A single weight measurement says little on its own - calculating the daily gain rate between two measurements reveals the actual growth trend, which is what pediatricians compare against expected ranges for a baby's age.
Worked example
For a baby gaining from 3,400g to 3,700g over 14 days:
Daily Gain Rate = (3700 - 3400) / 14 = 21.43 g/day
Commonly cited reference ranges suggest roughly 20-30 g/day for the first 3 months, gradually slowing over the first year as growth naturally decelerates - this result of 21.43 g/day falls comfortably within that typical early range.
This is informational only, not a substitute for your pediatrician's assessment, since healthy growth patterns vary between individual babies.