How we check sizes

Where the numbers come from

1. The brand’s own size chart first. We copy each size’s height and weight range (and waist, chest, hip, foot length or head size where the brand lists them) exactly as published, in the brand’s own units.
2. A retailer’s copy only when the brand’s chart can’t be read. Some brands post their chart as an image or behind a block. Then we use a store that reproduces the brand’s chart, and mark it in the table below.
3. No guessing. Every chart is read twice, and many have been compared again with a copy of the brand’s chart captured by the site owner. If a brand doesn’t publish measurements for a size or a type of clothing, that size isn’t offered as a measurement-based answer. Obvious slips in a brand’s chart are kept as published and noted, not quietly corrected.

How often we recheck

We recheck every brand’s chart at least twice a year, and whenever a reader tells us a size looks wrong. Brands do change their charts, so for an expensive purchase, glance at the brand’s own page too; every result links to it.

How the calculator picks a size

• We find the size that fits your child’s weight and the size that fits their height (plus waist, chest or hip if you enter them and the brand lists them).
• If they point to neighbouring sizes, the result says so and suggests the bigger one: a size that’s a little roomy still fits; one that’s too short in the body won’t close. If two sizes both fit, both are named.
• If a brand publishes a chart for the item you’re buying (for example a pants chart that uses waist), we use it. Otherwise we use the brand’s general chart only where the brand applies it to that item, and the result says why under “Why this chart”.
• Brands that size by height only are matched on height only. Some brands list weight for baby and toddler sizes but not for kids’ sizes; past those sizes we match on height and the other measurements the brand lists.
• Some brands cut girls’ and boys’ sizes differently. If you choose girl or boy, we use that chart. If you don’t, we use the girls’ chart and note the boys’ size when it’s different. Where a brand publishes Slim or Husky fits, you can choose them.

How the forecast works

When you add your child’s age, we compare their weight and height today with the World Health Organization growth standards for that age (the WHO growth reference for ages 5 and up, and the CDC growth charts for weight after age 10). We then assume they stay on the same growth curve and read off their likely weight and height at later ages. That gives the “Buying for 9 months?” answer and the size timeline.

Children grow in spurts, so treat forecast dates as estimates, especially more than six months ahead. Without an age, we use the WHO average for each age instead.

Sources for 109 brands

Search a brand to see where its size data comes from and when it was last checked. 108 brands use their own published chart; 1 uses a retailer’s copy.

Changes to the size data

Every change to a brand’s chart is recorded with its source. The newest are first.

Found a mistake?

Email amzad@babysizefinder.com with the brand, the size and what the brand’s chart says. We check every report and fix confirmed errors.