Find the right baby clothing size by weight and age. Size chart from Preemie to 24 months with brand comparison tips.
Baby clothing sizes are notoriously inconsistent across brands, making it hard to know what to buy. Most US baby clothing is sized by age range (Newborn, 0-3M, 3-6M, etc.), but weight is a more reliable guide since babies of the same age vary greatly in size.
Preemie sizes fit up to 5 lbs, Newborn fits up to 8 lbs, 0-3M fits 8-12 lbs, 3-6M fits 12-16 lbs, 6-9M fits 16-20 lbs, 9-12M fits 20-24 lbs, 12-18M fits 24-28 lbs, and 18-24M fits 28-32 lbs.
This calculator recommends a clothing size based on your baby's current weight and provides the weight range for that size. When in doubt, sizing up is always better — babies grow fast. Whether you are a beginner or experienced professional, this free online tool provides instant, reliable results without manual computation. By automating the calculation, you save time and reduce the risk of costly errors in your planning and decision-making process.
Avoid buying clothes your baby can't wear because they're already too small. This calculator helps you shop confidently by matching weight to size, whether buying in-store or online where you can't try things on. Having a precise figure at your fingertips empowers better planning and more confident decisions. Manual calculations are error-prone and time-consuming; this tool delivers verified results in seconds so you can focus on strategy.
Preemie: up to 5 lbs Newborn: up to 8 lbs 0-3M: 8-12 lbs 3-6M: 12-16 lbs 6-9M: 16-20 lbs 9-12M: 20-24 lbs 12-18M: 24-28 lbs 18-24M: 28-32 lbs 2T: 32-36 lbs
Result: Size 3-6M (12-16 lbs)
At 14 lbs, your baby fits best in 3-6M clothing. They're in the middle of the range, so current purchases in this size should last several weeks. Consider buying a few items in 6-9M for upcoming growth.
Baby clothing sizing varies significantly by brand, country of origin, and even product line within the same brand. A 6-month size from one brand may fit like a 9-month from another. This inconsistency makes weight-based sizing the most reliable approach.
Focus on basics: bodysuits, sleepers, and simple pants. Buy more in frequently-used sizes (3-6M and 6-9M) and fewer in sizes babies pass through quickly (Newborn). Watch for end-of-season sales to stock up on the next size.
Babies outgrow clothes before they wear them out. Consignment shops, Facebook Marketplace, and kids' clothing swaps offer significant savings. Sort hand-me-downs by size and store in labeled bins for easy access.
There's no universal sizing standard for baby clothes. Each brand creates its own size chart. European brands often use cm-based sizing, which is more precise. Always check the specific brand's size chart.
Buy by weight. A large 3-month-old may already be in 6-9M clothes. Weight is a much more accurate guide than age. Check the brand's weight chart on the tag or website.
Newborn size lasts 2-4 weeks for most babies. 0-3M lasts about 2-3 months. Each subsequent size lasts progressively longer. By 12-18M, babies may stay in a size for 3-4 months.
For gifts, buy 6-9M or 9-12M. Newborn gifts are often unusable because baby already outgrew the size or received too many in that size. Larger sizes are always appreciated.
For everyday wear: 7-10 bodysuits, 5-7 sleepers, and 3-5 outfits per size. Newborns need fewer fancy outfits and more functional basics. Reduce quantities as baby grows (they stay in sizes longer).
Start buying the next size when your baby is in the upper half of the current size's weight range. Watch for onesie snaps that are hard to close, sleepers that are tight at the feet, or pants that are too short.