Growth Velocity Calculator
Turn two height measurements into an annualised growth velocity in cm per year — the key metric for tracking a child’s growth.
How it works
Growth velocity (cm/year) = (later height − earlier height) ÷ months between × 12
Growth velocity — how fast a child is growing per year — is often more revealing than a single height measurement, because a child can be short yet growing at a healthy pace, or average yet slowing down. Clinicians annualise the gain between two visits and compare it to age-based norms: roughly 25 cm in the first year, tapering to about 5–6 cm/year through mid-childhood, then a spurt of 8–12 cm/year in puberty. A persistently low velocity is a reason to look closer.
Worked example
A child measured 100 cm, then 103 cm six months later. Gain is 3 cm; annualised: 3 ÷ 6 × 12 = 6 cm/year — a normal mid-childhood pace.
Frequently asked questions
How far apart should the two measurements be?
At least 4–6 months apart, ideally measured the same way each time. Over short intervals, small measurement errors get magnified when annualised, producing misleadingly high or low velocities.
What growth velocity is normal?
It depends on age: about 25 cm in year one, ~10 cm in year two, then roughly 5–6 cm/year until puberty, when it climbs to 8–12 cm/year. Compare to age-specific norms rather than one universal number.
My child’s velocity looks low — what should I do?
A single slow interval is often just measurement noise. If a genuinely low velocity persists across visits, a pediatrician can check for causes and plot it on a growth-velocity chart.
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This is a general educational estimate, not medical advice. Every child grows, feeds and responds to medicine differently — for anything about your child’s health, growth, nutrition or medication, follow the guidance of your pediatrician.