18 month old onesie

Most onesies are cotton-based: 100% cotton, cotton/polyester blends (for example 60% cotton/40% polyester), and pre-shrunk poly/cotton blends.

Pack sizes vary. Common options are single pieces, two-packs, and four-packs (four-packs are especially common for short-sleeve sets).

Look for reinforced seams and reinforced snap closures, pre-shrunk fabrics or blends, and double stitching (often used on graphic bodysuits).

Listings show both midweight and lightweight options: many short-sleeve cotton bodysuits are midweight, while some sleepers and novelty-print pieces are described as lightweight.

Common size listings include 12–18 months and 18–24 months. Some items also display full ranges (newborn up through 18–24 months).

Classic options include three-snap bottom closures and envelope (lap) shoulders. Many listings also mention reinforced snaps and expandable necklines to simplify dressing and diaper changes.

Care varies by item. Many list machine wash and tumble dry; some specify machine wash cold inside out and tumble dry low, while others note that hang-drying or line-drying gives the best results.

Common design elements include screen-printed quotes and graphics, glitter or textured accents, character or book-quote prints, and officially licensed designs.

Footed sleepers commonly include built-in footies, full-length zipper closures, protective zipper guards or snap tabs at the neckline, fold-over scratch mitts, and sometimes non-slip grips on the soles.