# At What Age Is the WHO-GMM Used for a Child?

Canonical: https://pinnacleblooms.org/ask/at-what-age-is-the-who-gmm-developmental-assessment-used-for-a-child
Publisher: Pinnacle Blooms Network / Bharath Healthcare Laboratories Private Limited

The WHO Windows of Achievement for Gross Motor Milestones (WHO-GMM) is used for infants and young children, roughly from 4 months to about 24 months of age. It maps the typical age window in which most healthy children reach six key gross-motor milestones — sitting, crawling, standing and walking. Each milestone has a window rather than a single deadline, allowing for normal variation, and it serves as a reference to notice when a milestone falls outside its expected range.

*A handy ruler for the early walking years — the WHO-GMM tells us the typical age range in which a child reaches each big motor milestone.*

## In short
The **WHO Windows of Achievement for Gross Motor Milestones (WHO-GMM)** is used for **infants and young children, roughly from 4 months to about 24 months (2 years)** of age. It maps the typical age *window* in which most healthy children reach six key gross-motor milestones — sitting, standing, crawling and the early steps of walking. It is a reassuring reference for the early movement years, not a test that continues into the school years.

## What the WHO-GMM covers and when
The WHO-GMM describes six gross-motor milestones, each with a *window* — an early-to-late age range rather than a single deadline — that reflects how much healthy variation is normal between babies. In broad terms these windows span:

- **Sitting without support** — from around 4 months
- **Hands-and-knees crawling** — from around 5–6 months
- **Standing with assistance** — from around 5–6 months
- **Walking with assistance** — from around 6 months
- **Standing alone** — from around 7 months
- **Walking alone** — typically by around 18 months, with the window extending towards 18–24 months

Because each milestone has a window, a baby who sits or walks a little earlier or later than a friend is usually still developing perfectly well. The WHO-GMM simply helps families and clinicians notice when a milestone falls outside its expected window, which is a gentle prompt for a closer look — never an automatic concern on its own.

## When a review helps
Consider a developmental review if your child has clearly passed the later edge of a window without reaching that milestone — for example, not sitting independently well beyond the sitting window, or not walking by around 18 months — or if you notice stiffness, floppiness, or one side of the body being used much less than the other. Early observation protects a child's movement, confidence and play.

## The Pinnacle way
This is general information, not a diagnosis — a clinical [AbilityScore®](/ask/what-is-the-abilityscore-and-how-is-it-calculated) and any diagnosis are formed only at a Pinnacle Blooms Network centre, under qualified clinician care, never from an app or form. Our team uses references like the [WHO-GMM](/who-gmm) alongside a full developmental picture, then shapes any helpful support, which may include [occupational therapy](https://www.pinnacleblooms.org/best-occupational-therapy-center-india-proven-improvement-rate) for movement and play skills.

## Trusted sources
WHO Multicentre Growth Reference Study, which established the Windows of Achievement for the six gross-motor milestones; WHO Nurturing Care Framework on early childhood development; CDC and AAP/HealthyChildren guidance on motor milestones.

**Next step —** If your child is in the early walking years and you'd like reassurance about their movement milestones, book a developmental review to map their progress against the expected windows.

## Sources
- WHO Child Growth Standards & Motor Milestones: https://www.who.int/tools/child-growth-standards
- CDC Developmental Milestones: https://www.cdc.gov/child-development
- AAP HealthyChildren on infant milestones: https://www.healthychildren.org

## Connected topics and perspectives
- Assessments: https://pinnacleblooms.org/ask/assessments
- Parent: https://pinnacleblooms.org/ask/lens/stakeholder/parent
- Definition: https://pinnacleblooms.org/ask/lens/intent/definition
- Measure: https://pinnacleblooms.org/ask/lens/lifecycle/measure
- Screen: https://pinnacleblooms.org/ask/lens/route/screen
- Early Clarity: https://pinnacleblooms.org/ask/lens/empowerment/early_clarity

## Related question paths

### Understand the subject
- What is the WHO Windows of Achievement for Gross Motor Milestones (WHO-GMM)?: https://pinnacleblooms.org/ask/what-is-the-who-windows-of-achievement-for-gross-motor-milestones-who-gmm-and-what-does-it-assess
- At what age is the GMFM developmental assessment used for a child?: https://pinnacleblooms.org/ask/at-what-age-is-the-gmfm-developmental-assessment-used-for-a-child

### Recognise signs & concerns
- Key motor milestones in early childhood: https://pinnacleblooms.org/ask/what-are-the-key-motor-milestones-in-early-childhood

### Understand assessment
- Should My Child Have a WHO-GMM Assessment?: https://pinnacleblooms.org/ask/should-my-child-have-a-who-gmm-assessment-and-what-does-it-involve
- When is the WHO-GMM indicated, and what are its strengths and limits?: https://pinnacleblooms.org/ask/when-is-the-who-gmm-indicated-and-what-are-its-strengths-and-limits-in-early-childhood
- How does the WHO-GMM compare with the AbilityScore developmental assessment?: https://pinnacleblooms.org/ask/how-does-the-who-gmm-compare-with-the-abilityscore-developmental-assessment