How to Swaddle a Baby
A snug swaddle can calm a newborn's startle reflex and help everyone sleep. Here's how to do it right — and the one rule that matters most: stop at the first sign of rolling.
A good swaddle recreates the snug, contained feeling of the womb and can dampen the startle reflex that jolts newborns awake. Done right, it's a genuinely useful settling tool for the early weeks. Done wrong, it introduces risk. Two rules govern everything below: a swaddled baby always sleeps on their back, and you stop swaddling at the first signs your baby is trying to roll. Keep those two in mind and the technique is simple.
This guidance follows AAP and safe-sleep recommendations. If you'd rather use a ready-made wrap or zip swaddle than a blanket, our best swaddles roundup covers the options; the safety rules are the same either way.
How to swaddle with a blanket, step by step
- Lay a thin, square blanket flat in a diamond and fold the top corner down a few inches to make a straight edge.
- Place your baby face-up with their shoulders just below the folded edge, head above the blanket.
- Gently straighten one arm down along the body and wrap that side of the blanket snugly across the chest, tucking it under the opposite side.
- Fold the bottom corner up over the feet, leaving room for the legs to bend.
- Straighten the other arm down, wrap the remaining side across, and tuck it so the swaddle is secure but not tight around the hips.
The finished swaddle should be snug across the arms and chest so the startle reflex is contained, and loose around the hips and legsso the legs can bend up and out. It shouldn't be so loose that fabric can work free and cover the face.
Snug arms, loose hips — and why the hips matter
Wrapping a baby's legs tightly and straight down is associated with hip problems, because it forces the hips out of their natural bent, spread position. Leave room for the legs to move into that frog-like posture. If you use a wrap or sack, the same rule applies: firm around the torso, generous around the hips. A too-tight, straight-leg swaddle is the mistake to avoid.
Always on the back — never side or stomach
A swaddled baby must be placed on their backfor every sleep, on a firm, flat surface with nothing loose around them. Side and stomach positions are unsafe for a swaddled baby — even more so than usual, because a swaddled baby can't use their arms to reposition or push up. Follow the full list in our safe-sleep guidelines.
Don't overheat
A swaddle adds warmth, so watch for overheating: use a thin, breathable fabric, keep the room comfortable, and dress your baby lightly underneath. Signs of overheating include sweating, flushed cheeks, and a hot chest or neck. Our guide to TOG and room temperature explains how to dress a baby for sleep without over-bundling.
When to stop: the first signs of rolling
This is the most important rule, so it gets its own section. As soon as your baby shows any signs of trying to roll— often somewhere around 2 to 4 months, but it varies — swaddling with the arms in is done. A swaddled baby who rolls to their stomach can't push up or turn their head freely, which is dangerous. Transition to an arms-free wearable blanket or sleep sack; many families ease the change with a transition product that frees one arm at a time. Our guide on when to stop swaddling walks through the timing and the signs to watch for. When in doubt, stop earlier rather than later.