Newborn Weight Change Calculator
Check how much a newborn has lost or regained since birth.
Your result
Most newborns lose up to about 7–10% in the first week and regain it by about two weeks old. Losing more than 10%, or not regaining, needs prompt review.
Medical disclaimer: This tool is for education and is not medical advice. Read more.
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Frequently asked questions
What does the Newborn Weight Change Calculator do?
Check how much a newborn has lost or regained since birth. Enter your values and the result and chart update instantly.
How accurate is it?
It uses published, widely used formulas. Results are estimates for education and planning, not a diagnosis. Talk to a qualified clinician about decisions affecting your health.
Is my information stored or shared?
No. All calculations run in your browser and nothing you type is sent to a server or saved.
What can I search to find this tool?
People find it by searching for: how much weight should baby lose; newborn weight loss percent; baby weight regain.