The short answer

Do not measure height every day or every week to look for skeletal growth. For an older child, six months is a typical clinical time frame when growth rate is being assessed, although the right schedule depends on age, health context and a clinician’s guidance.

GetTall’s free growth-velocity calculator requires measurements at least 90 days apart. That is a product guardrail against very short intervals, not a medical recommendation to measure every three months.

Why short intervals mislead

Suppose one measurement is off by only 0.1 cm. Annualizing that difference across one week makes it look like about 5.2 cm per year. Across three months it is about 0.4 cm per year; across six months, about 0.2 cm per year. The same tiny error looks much larger when the interval is short.

Practical rule: improve the consistency of each measurement before increasing the frequency.

A sensible home-tracking approach

  1. Use routine clinical measurements as the primary record whenever possible.
  2. If you also measure at home, use the same wall, floor, technique and approximate time of day.
  3. Record the exact date rather than “about three months ago.”
  4. Leave months between measurements unless a clinician gives different instructions.
  5. Do not interpret one surprising result before rechecking the setup.

When the schedule should come from a clinician

Age under 2, a known health condition, medication monitoring, a change in growth pattern or an existing clinical concern can all change how and when measurements should be taken. In those situations, follow the pediatrician’s schedule rather than a generic web guide.

What to record with the number

  • date and approximate time;
  • height and unit;
  • shoes on or off;
  • wall, floor and measuring device;
  • anything that made the measurement difficult.

Sources