The Science Behind Baby Safety: When Do Babies Start Crawling?

You've heard the advice a thousand times: childproof before your baby starts crawling. But when is that, exactly? And what does the science actually tell us about how babies develop mobility?

Let's get into it.

The Average Timeline

Most babies start crawling between 6 and 10 months old, with the average landing around 8 months. But "average" covers a huge range of normal. Some babies crawl at 5 months. Others skip crawling entirely and go straight to walking at 9-10 months.

Here's what the research from the World Health Organization's Multicentre Growth Reference Study tells us:

Sitting without support: 4-9 months (average 6 months)

Crawling on hands and knees: 5-13.5 months (average 8.5 months)

Standing with assistance: 5-11 months (average 7.6 months)

Walking with assistance: 6-13 months (average 9.2 months)

Standing alone: 7-17 months (average 11 months)

Walking alone: 8-18 months (average 12.1 months)

Notice those ranges. A baby who walks at 8 months and one who walks at 18 months are both completely normal.

Why This Matters for Safety

The ranges are the important part. If you wait until your baby "shows signs" of crawling to start childproofing, you're already behind. Some babies go from sitting to speed-crawling in what feels like a weekend.

The safe approach: have your basic childproofing done by 4-5 months. That gives you a buffer before even the earliest crawlers get moving.

Different Styles of Movement

Not every baby crawls the "traditional" way on hands and knees. Researchers have documented several distinct movement patterns:

Classic crawling: Hands and knees, alternating limbs

Army crawling: Belly on the ground, pulling with arms

Bear crawling: Hands and feet, bottom in the air

Scooting: Sitting up and using arms to scoot forward

Rolling: Just rolling across the room to get where they want

Cruising: Skipping crawling, pulling up and walking along furniture

All of these are normal. And all of them mean your baby can now reach things that were previously safe.

Speed Development

What catches parents off guard is how fast babies get fast. A baby who just started crawling covers maybe 10 feet per minute. Within a few weeks, that same baby can cross a room before you finish pouring your coffee.

Studies show that experienced crawlers move at about 30-40 feet per minute. That's fast enough to reach the stairs, the kitchen, or the bathroom before you can react if you're not paying attention.

The Brain-Body Connection

Here's something interesting from the research: babies don't just develop motor skills. Their risk perception develops at the same time, but much more slowly. A crawling baby has the ability to reach dangerous places but not the judgment to avoid them.

Visual cliff experiments show that experienced crawlers develop some fear of heights, but it takes weeks to months of crawling experience. New crawlers will happily crawl right off an edge.

What to Do With This Information

Childproof at 4 months, before you need it

Re-evaluate monthly as skills develop

Don't assume your baby will follow the "average" timeline

Remember that mobility develops faster than judgment

The science gives us a clear message: prepare early, update often, and never assume your baby can't reach something just because they couldn't yesterday.