When Do Babies Start Walking? The WHO Window, Read Properly

When babies start walking, using the WHO's actual published window rather than the rounded version — the real range is wider at the bottom and narrower at the top than almost every article says. Read from the WHO's own table.

This article exists because we published a version of it that cited this exact study as "9 to 18 months". So the table comes first.

The WHO windows, as published

The WHO Multicentre Growth Reference Study publishes windows of achievement — the range within which healthy children reach each milestone — rather than single ages. One correction to our own earlier version before the numbers: the motor-milestone data did not come from all six of the study's countries. It came from five. The WHO's paper says motor data were collected in "five sites: Ghana, India, Norway, Oman and the USA", because "the study was already well under way in Brazil when the decision to add this component was made". The windows below rest on 816 children, assessed by trained fieldworkers at home visits monthly from 4 to 12 months and bimonthly to 24 months (WHO Motor Development Study, Acta Paediatrica Supplement 2006).

And a qualification the WHO attaches itself, which belongs here rather than in a footnote: this is a standard, not a description of babies in general. The sample was deliberately privileged — "healthy children living under conditions that are highly unlikely to constrain growth", whose mothers breastfed and did not smoke. In the WHO's words, "a standard defines how children should grow", and references, unlike standards, are "not a sound basis for such judgements, although in practice references are often misused as standards". Read the windows as what healthy, well-supported babies did, not as a census of every baby.

Milestone	Window (months)	95% CI, lower bound	95% CI, upper bound
Sitting without support	3.8 – 9.2	3.7 – 3.9	8.9 – 9.4
Standing with assistance	4.8 – 11.4	4.7 – 5.0	11.2 – 11.7
Hands-and-knees crawling	5.2 – 13.5	5.0 – 5.3	13.1 – 13.9
Walking with assistance	6.0 – 13.7	5.8 – 6.1	13.4 – 14.1
Standing alone	6.9 – 16.9	6.8 – 7.1	16.4 – 17.4
Walking alone	8.2 – 17.6	8.0 – 8.4	17.1 – 18.0

Two things worth noticing. The bottom of the walking window is 8.2 months, not 9 — babies who walk before nine months are inside the normal range, not exceptional. And the top is 17.6, not 18.

The difference sounds pedantic until you are the parent of a seventeen-month-old reading an article that says the window closes at eighteen.

Four small disagreements between the WHO's own two documents, which we are not going to hide. The summary table gives the lower bound for walking with assistance as 6.0 months; Table II of the full paper gives 5.9. Three confidence-interval ends differ by a tenth of a month as well, always in the same direction: the paper opens standing with assistance's upper interval at 11.1 where the table says 11.2, hands-and-knees crawling's upper interval at 13.0 where the table says 13.1, and standing alone's lower interval at 6.7 where the table says 6.8 (WHO Motor Development Study, Table II). Every other figure is identical in the two documents, the walking-alone row included. We have printed the summary table's numbers throughout, because that table is the document these six rows are quoted from.

What comes before walking, and in what order

The windows overlap heavily, which is the more useful observation than the sequence.

A baby can be sitting without support at four months or at nine. One can be crawling at five months while another has not started at twelve and is inside the window until 13.5. And standing alone opens at 6.9 months, ten months before its own window closes.

The practical consequence: comparing two babies of the same age tells you almost nothing. Two twelve-month-olds, one walking confidently and one not yet standing alone, are both unremarkable.

Crawling is not a prerequisite

Worth its own section because it causes disproportionate worry.

The WHO lists hands-and-knees crawling as one of six gross motor milestones with its own window of 5.2 to 13.5 months. What the study actually found is more specific than "order does not matter". In about 90% of cases the other five milestones — sitting without support, standing with assistance, walking with assistance, standing alone and walking alone — did follow a fixed sequence, "with only hands-and-knees crawling shifting in between the earlier milestones". Crawling is the one that moves. And 35 of the 816 children, 4.3% of the sample, "did not exhibit hands-and-knees crawling" at any point (WHO Motor Development Study).

The WHO's paper notes that those children used some other form of locomotion instead, "such as bottom shuffle or crawling on the stomach". The AAP says the same thing in plainer words: "A few children never crawl. Instead, they use alternative methods, such as scooting on their bottoms or slithering on their stomachs" (AAP, Movement: 8 to 12 Months). The condition the AAP attaches on that same page is the one to hold onto: what matters is that a baby is "coordinating each side of her body and using each arm and leg equally". If you are worried about it, that is a conversation for your child's doctor — but the absence of hands-and-knees crawling on its own is not the alarming fact the internet often makes it.

Signs walking is close

Editorial judgment rather than research findings, and marked as such — the WHO publishes windows, not warning signs.

Pulling to stand on anything. Furniture, legs, the dog. This is usually the first strong signal.

Cruising sideways along furniture. The gap between cruising and independent steps is often weeks rather than months, but it varies wildly.

Standing unsupported without noticing. Often accidental at first — they let go and stay up because they are distracted.

Squatting and standing back up. Requires the strength and balance walking needs.

Refusing to be carried. Not a clinical sign, but a fairly reliable domestic one.

What not to do

Do not compare to a specific other baby. The windows are wide enough that any two babies are a meaningless sample.

Do not treat a walker as an accelerator. The AAP is blunt about this: "Many parents think walkers will help their children learn to walk. But they don't. In fact, walkers can actually delay when a child starts to walk." The same page states that the AAP "has called for a ban on the manufacture and sale of baby walkers with wheels", and that Canada already bans them (AAP, Baby Walkers: A Dangerous Choice). Be exact about who says what, though: the United States has not banned walkers. It regulates them, under a mandatory standard that applies to walkers manufactured or imported on or after 21 December 2010 (16 CFR Part 1216). Ask your child's doctor rather than an activity blog.

Do not read a rounded window as the real one. "9 to 18 months" appears everywhere and is not what the study says.

Do not use this article to decide whether to worry. The AAP recommends developmental surveillance at every health supervision visit, and standardised developmental screening at the 9-, 18- and 30-month visits. Those visits are the mechanism. A blog post is not.

Where a book fits, and where it does not

We make illustrated hardcover books from families' own memories, so read this as interested rather than neutral.

The honest case is small: this is an informational article, and if you are here because you are worried about a seventeen-month-old, we are not the answer and neither is any purchase. The table above is the answer, and after that, your child's doctor.

Where a book genuinely fits is afterwards. Our own observation rather than a research finding, and we are marking it as such: first steps happen without warning and usually with nobody holding a phone, which is why so many families end up with no footage of them. The baby's first steps book page covers that single moment, the milestones keepsake page covers the whole year rather than the one event, and the first birthday book is the version people ask for when the walking and the birthday land within a few weeks of each other. Our milestones and screening article covers the full set of windows and the schedule of checks.

If you came here for reassurance rather than a keepsake, take the reassurance and ignore the rest of this section.

Frequently asked questions

When do babies start walking?

The WHO's window of achievement for walking alone is 8.2 to 17.6 months, with 95% confidence intervals of 8.0–8.4 at the lower bound and 17.1–18.0 at the upper. The widely repeated "9 to 18 months" is a rounded version that is wrong at both ends.

Is it normal for a baby not to walk at 14 months?

It is inside the published window, which runs to 17.6 months. So is not walking at 16 months. That is a statement about the range, not about your individual child — for that, the AAP's mechanism is developmental surveillance at every health supervision visit, plus standardised screening at 9, 18 and 30 months.

Do babies have to crawl before they walk?

No. The WHO lists hands-and-knees crawling as one of six gross motor milestones with its own window of 5.2 to 13.5 months, not as a prerequisite for walking, and in its own sample 35 children out of 816 — 4.3% — never crawled on hands and knees at all. The AAP describes the same thing: a few children never crawl and instead scoot on their bottoms or slither on their stomachs.

What are the signs a baby will walk soon?

Pulling to stand on anything, cruising sideways along furniture, standing unsupported without appearing to notice, and squatting then standing back up. These are observations rather than research findings — the WHO publishes windows, not predictive signs.

What comes before walking?

On the WHO's windows: sitting without support 3.8–9.2 months, standing with assistance 4.8–11.4, hands-and-knees crawling 5.2–13.5, walking with assistance 6.0–13.7, standing alone 6.9–16.9. The windows overlap heavily, which is why comparing two babies of the same age tells you very little.

Should you be worried if a baby walks very early?

Walking before nine months sits inside the published window, whose lower bound is 8.2 months. Early is not the same as abnormal. As with the other end of the range, individual concerns belong with your child's doctor rather than with an article.

How this guide was made

The WHO figures were extracted from the WHO's own published windows-of-achievement table using pdftotext, not taken from a page describing it. That matters here more than anywhere else on this blog: the version of this article we published previously cited this exact study as "9 to 18 months", and the statistics audit found the same error repeated four separate times across our own site. Nobody was inventing anything — they were repeating a rounded figure that circulates widely. The primary document does not round.

Three statements in the earlier version of this article were wrong, and have been corrected in place rather than quietly deleted. It said the motor-development data was gathered across children in six countries; the WHO's own paper says five sites, because Brazil had already started fieldwork when the motor component was added. It described "healthy children" while linking only to the one-page summary table, which contains six rows of numbers and no methodology at all — the phrase, the selection criteria and the standard-versus-reference caveat are in the full paper, and the full paper is now what those sentences link to. And it asserted that the study does not treat the six milestones as a sequence; in fact the study reports a fixed sequence in about 90% of cases for five of them, with crawling the one that shifts. That qualification cuts against the simpler version we had written, so it is now in the body.

Two claims were dropped because nothing we could open supported them. The first was a line saying that first steps are among the milestones parents most wish they had recorded. It rested on no named survey, and no page we opened states it, so the reason we give for making a book of it is now marked as our own observation instead, and it makes no claim about how first steps rank against any other milestone. The second was an appeal to unnamed safety authorities having concerns about baby walkers. That named nobody, so it has been replaced by what the AAP actually says on its own consumer page, plus the separate and different fact that the United States regulates walkers rather than banning them. We wanted CPSC's own site as the citation for that second half and could not have it — cpsc.gov returned 403 to every request we made — so the regulation itself is cited in its place.

The signs-walking-is-close section is explicitly marked as editorial judgment, because the WHO publishes windows and not predictive signs, and we are not going to blur that line.

Nothing here is medical advice, and the article says five separate times that individual concerns belong with a doctor.

Sources

• WHO Multicentre Growth Reference Study Group, "WHO Motor Development Study: Windows of achievement for six gross motor development milestones" — Acta Paediatrica Supplement 2006;450:86–95. 816 children in five sites (Ghana, India, Norway, Oman, the USA), assessed at home visits monthly from 4 to 12 months and bimonthly to 24 months. Source of the five-site sample, the healthy-children selection criteria, the standard-versus-reference caveat, the fixed sequence in about 90% of cases, the 4.3% who never crawled on hands and knees, and (Table II) the percentile figures that differ by a tenth of a month from the summary table. who.int (PDF)
• WHO, "Windows of achievement for six gross motor milestones" — the one-page summary table from the same study. Source of every window and confidence interval in the table above, read from WHO's own published table. who.int (PDF)
• American Academy of Pediatrics, "Baby Walkers: A Dangerous Choice" — HealthyChildren.org, last updated 15 August 2022. Source of the AAP's position that walkers do not help a child learn to walk and can delay walking, and of its call for a ban on the manufacture and sale of baby walkers with wheels. healthychildren.org
• American Academy of Pediatrics, "Movement: 8 to 12 Months" — HealthyChildren.org. Source of the description of babies who never crawl and use scooting or slithering instead, and of the coordination condition attached to it. healthychildren.org
• 16 CFR Part 1216, Safety Standard for Infant Walkers — the current US mandatory standard, source 75 FR 35273 (21 June 2010), most recently amended at 87 FR 73245 (29 November 2022). Source of the fact that walkers manufactured or imported into the United States on or after 21 December 2010 are regulated rather than banned. ecfr.gov
• American Academy of Pediatrics, "Developmental Surveillance and Screening" — source of the guidance that developmental surveillance occurs at every health supervision visit, with standardised developmental screening at the 9-, 18- and 30-month visits. aap.org