Zipadee-Zip Sizing Guide: Find the Perfect Fit for Your Baby

Getting the right size for your baby’s Zipadee-Zip sleep sack is key to safe, comfortable sleep. A proper fit helps your little one move freely while keeping them snug and secure. This guide walks you through the size chart, how to measure your baby, and what to look for when choosing between small, medium, or large.

Whether you’re buying your first Zipadee-Zip or sizing up as your baby grows, we’ll cover the details so you can feel confident about your choice. Let’s start with the basics.

Understanding the Zipadee-Zip Size Chart

The Zipadee-Zip comes in small, medium, and large sizes, each designed for a specific weight range. Small fits babies from 8 to 13 pounds, medium from 13 to 20 pounds, and large from 20 to 30 pounds. These ranges are based on average baby growth, so always check your baby’s current weight before ordering.

Keep in mind that the Zipadee-Zip is meant to be a roomy, starfish-like shape that allows your baby to move their arms and legs. A snug fit isn’t necessary—the sleep sack should be loose enough for them to roll over and self-soothe, but not so big that fabric bunches near their face. For a safe fit, the neck opening should be snug but not tight, and the wings should extend past your baby’s fingertips.

• Small: 8–13 lbs (ideal for newborns and early infants)
• Medium: 13–20 lbs (covers most babies through the first year)
• Large: 20–30 lbs (for toddlers and bigger babies)

How to Measure Your Baby for the Right Size

To find the best fit, start by weighing your baby. If you don’t have a scale at home, use their most recent pediatrician weight. Next, measure their length from the top of their head to the bottom of their feet. The Zipadee-Zip is designed to accommodate a range of lengths within each weight bracket, so you don’t need to worry about exact height.

If your baby is between sizes—say, 12.5 pounds—choose the smaller size if they are still under 13 pounds. The sleep sack should feel snug around the chest and neck without being tight. If they are close to the upper limit of a size, sizing up is usually fine, but check that the fabric doesn’t bunch around their face. The Classic Zipadee-Zip Swaddle Transition and the EverSoft Bamboo Zipadee-Zip Swaddle Transition both follow the same size chart, so you can use the same measurements for either fabric.

• Weigh your baby and compare to the size chart.
• Check that the neck opening fits two fingers between fabric and skin.
• Make sure the wings extend past fingertips to prevent chewing.

When to Size Up: Signs Your Baby Needs a Larger Zipadee-Zip

Babies grow quickly, and you might notice your little one is ready for a larger size before you expect. Common signs include the sleep sack feeling tight around the chest or shoulders, the fabric pulling at the neck, or your baby struggling to move their arms and legs freely. If the wings are too short to cover their hands, they may start chewing on the fabric, which is a clear sign to size up.

Another clue is if your baby’s feet are pressing against the bottom of the sleep sack. The Zipadee-Zip is designed with a bit of extra length, but if their toes are constantly pushing against the seam, it’s time for a larger size. For example, the Sleeping Baby Classic Zipadee-Zip Swaddle Transition in medium works well for most babies around 15–18 pounds, but once they hit 20 pounds, the large size gives them more room to stretch.

• Tightness around the chest or shoulders.
• Wings no longer cover fingertips.
• Feet push against the bottom of the sleep sack.

Choosing Between Small, Medium, and Large for Your Baby’s Age

While weight is the primary factor, age can also guide your choice. Small is typically for newborns up to about 3 months, medium for 3 to 9 months, and large for 9 to 18 months. However, every baby grows differently, so always rely on weight first. If your baby is 4 months old but weighs 14 pounds, medium is the right pick.

For babies who are transitioning out of a swaddle, the Zipadee-Zip in small or medium is a great starting point. The Classic Zipadee-Zip Swaddle Transition and the EverSoft Bamboo Zipadee-Zip Swaddle Transition both offer the same sizing, so you can choose based on fabric preference. The bamboo version is softer and more breathable, which some parents prefer for warmer months, but the sizing is identical.

• Small: 0–3 months (8–13 lbs)
• Medium: 3–9 months (13–20 lbs)
• Large: 9–18 months (20–30 lbs)

Finding the right Zipadee-Zip size doesn’t have to be tricky. Focus on your baby’s weight, check the fit around the neck and chest, and watch for signs they’re ready to size up. With the Classic Zipadee-Zip Swaddle Transition or the EverSoft Bamboo version, you’ll have a safe, comfortable sleep sack that grows with your little one.