Adult Onesie Sizing Guide: Find Your Fleece Onesie Size

A onesie is only as cozy as its fit. Too small and the shoulders pull every time you reach for the remote; too big and the fleece bunches where you sit. Because every Cherry Mavericks onesie is made to order and personalized with your design, an exchange is not as simple as swapping a size off a rack, so it pays to spend three minutes with a tape measure before you order. This guide gives you the full fleece size chart, explains how a onesie should fit, and shows you how to measure your chest, waist and hips the same way we size our suits.

The size chart

Our fleece onesies are sized by body measurements, not by height alone. Find your chest, waist and hip measurements below and match them to the closest size. All measurements are in centimeters first, with inches alongside.

If your measurements land between two sizes, we recommend the larger one for a lounge fit. Fleece onesies are worn for hours at a time, and a little extra room is comfort, not sloppiness.

How a onesie should fit: relaxed vs snug

There are two schools of onesie fit, and neither is wrong. A relaxed fit drapes away from the body, leaves room for a t-shirt underneath, and feels like wearing a blanket. Most of our customers choose this fit for footed pajamas, movie nights and matching family sets, and it is the safer choice if you are between sizes. A snug fit follows the body more closely, with less fabric at the legs and seat. It suits people who wear a onesie as a costume base or who simply dislike loose fabric. Our chart is cut with a lounge fit in mind, so if you want a closer fit, you can choose the smaller of two sizes when your measurements sit right on the line. Either way, the shoulders should sit at your natural shoulder line and the zipper should close without pulling.

How to measure: chest, waist and hips

Use a soft tape measure over light clothing, and stand relaxed rather than holding your breath. Chest: wrap the tape around the fullest part of your chest, under your arms, keeping it level across your back. The tape should be snug, not tight. Waist: measure around your natural waistline, the narrowest part of your torso, usually just above the navel. Do not use your jeans size; trouser sizing and body measurement are often two different numbers. Hips: stand with your feet together and measure around the fullest part of your hips and seat. Write the three numbers down and compare them with the chart above. Your onesie size is the one that fits your largest measurement comfortably, because the zipper has to close over chest, waist and hips in a single piece of fabric.

Footed vs non-footed fit notes

Fit works slightly differently depending on the style. Our fleece onesies are footed, which means the legs end in enclosed feet. With a footed design, your height matters as well as your measurements: if you are tall for your size, or close to the top of a size range, choose the larger size so your toes have room when you stretch out. A footed suit that is too short pulls at the shoulders every time you sit down. Non-footed styles, like our sherpa zip-up rompers, end at the ankle and are more forgiving on length, so your chest and hip measurements are the only numbers that really decide the size. Whichever style you pick, try the zipper path in your head: the suit should close smoothly without the fabric pulling across the chest.

Plus sizes and the 2XL note

Our onesies are sold up to 2XL, so most plus size shoppers are covered. One honest note about the chart: it lists garment measurements up to XL. 2XL is available on the product page; if you need its measurements, contact us and we will confirm before you order. That way you get exact numbers for the biggest size rather than a guess. And if your measurements fall outside the chart entirely, a custom size is available on request. Contact us with your chest, waist and hip measurements and we will confirm the fit before you pay.

Frequently asked questions

What if I am between sizes?

Choose the larger size. A relaxed fit is the comfortable default for fleece onesies, especially footed styles.

Do you offer a custom size?

Yes. The size chart lists a Custom option: contact us with your measurements and we will confirm the size before you order.

Should I size up if I want to wear clothes underneath?

Yes. If you plan to wear a t-shirt or base layer under your onesie, the larger of two sizes will feel better.

Are the kids sizes on the same chart?

This chart covers the fleece onesie range. If you are ordering for a child and cannot find the right fit, contact us and we will help you match measurements to a size.

Ready to order? Browse the fleece onesies, rompers and footed pajamas in the One-Pieces collection, pick your colorway and add your own artwork: /collections/one-pieces