When it comes to baby clothing, finding the right fit can feel like cracking the DaVinci code. While many clothing manufacturers size based on age, infants grow at their own pace and often outgrow clothes before they can even be worn. That is why it is important to learn the nuances of baby clothing sizes and use a baby clothing chart to help you make the most informed purchase.

Whether you’re looking to buy clothes for your own baby, or you are shopping for a friend or loved one, knowing how baby clothing sizes work will ensure that the perfect outfit is on hand for every milestone. To help you, we’ve broken down the complexities of infant clothing sizes and compiled a handy baby clothing chart to make your next shopping trip more streamlined.

Many parents start off their baby wardrobes with a lot of newborn sizes (size 0000) and then upgrade to 0-3 months or 3-6 month clothes once they outgrow them. Using an infant clothing chart can help you decide what sizes to get if you’re not sure, but remember that the sizing will vary depending on your baby’s height and weight.

If you’re shopping with a European brand, it is worth noting that their sizing is typically labeled based on maximum centimeters in height — so while a 3-6 month size might fit your infant, a 3 or 4 month size might be more appropriate. To compare sizes, you can look up their sizing on the manufacturer’s website or review a conversion table.

Another thing to consider is the fabric type and stretch of a garment. Some fabrics may shrink with repeated washing, so you may want to go up a size when possible. Likewise, some garments have snaps or zippers at the bottom that can be opened for a little extra room.

The best way to know if a garment is the right size for your baby is to measure them yourself. You can use a tape measure to accurately assess chest circumference and arm length. For inseam, it’s easiest to have the child stand while you measure. You can also use a soft measuring tape, such as the ones used for newborns. Just be sure to not pull the tape too tight or it may be too small. It’s also a good idea to have the baby wear a shirt or dress so you can get a better gauge of their body.