Kids Clothing Size Calculator
Compares a child's height, chest and waist with a size chart, where chest and waist can rule a size out, with an optional growth-room scenario.
Measurements
Standing straight against a wall, without shoes.
Around the fullest part of the chest, under the arms, tape level.
Around the natural waist, over light clothing.
No name, birth date or photo is asked for, and nothing typed here is saved.
Illustrative chart — not a brand chartZerdly (illustrative) · Children's clothing (body height, chest, waist) · version 2026-10-08
Room to grow — your own scenario
Add the room you want (for example 4 cm of height). This shifts the comparison only as a clearly marked scenario; it does not predict growth.
Result
Enter the child's height (and chest and waist if you can) to compare with the chart.
Before you rely on this: Use this as a quick guide and check the result against your own working before you rely on it.
How to use this calculator
- Measure the child's height against a wall without shoes, then chest and waist if you can. Height is required; anything you leave blank is shown as not measured.
- Use the illustrative chart, or enter the size chart of the shop you are buying from.
- Optionally add your own growth room as a scenario. For garments that must fit snugly, such as sleepwear, follow the manufacturer's size instead.
How it works
Height is the main measurement, but chest and waist are real limits: a size the chest is too big for is ranked below one that fits, whatever the height says. Sizes are ranked by how many measurements they are too small for, then by how far outside their ranges the child is.
If no size covers every measurement the tool says so instead of returning a guaranteed size, and a height on a boundary can belong to two sizes. Growth room is only ever the number you type in: nothing predicts growth, and no size is added automatically.
Worked example
Height 120, chest 63, waist 57 cm, on the illustrative chart. All three sit inside size 7 (117–123 cm height, 62–65 cm chest, 56–58 cm waist), so size 7 is the match. With a 70 cm chest, size 7 is too small at the chest, so it ranks below size 10, whose chest range of 68–72 cm covers it — and the result shows that size 10 is long for a 120 cm child.
Tips
- Measure height against a wall without shoes.
- Measure over light clothing and keep the tape level.
Frequently asked questions
Should I use age or measurements?
Measurements. Children of the same age differ widely, and an age on a label is only the brand's description — clothing labels are not a health or development assessment.
Should I just buy a size up?
Only if you want to — the tool does not assume it. Add the room you want as a scenario to see which size that points to and where it would be loose now. Never add room to garments that must fit snugly.
Why does the built-in chart say illustrative?
Because it is. Zerdly has not verified the right to republish any brand's size chart, so the built-in ranges are Zerdly's own round numbers, labelled as such. For a real purchase, enter the size chart of the shop you are buying from — it takes a minute and the comparison then uses that shop's own labels.
Related tools
- Shoe Size Calculator
- Clothing Size Finder
- Dress Size Calculator
- Bra Size Calculator
- Jeans Size Calculator
- Shirt Size Calculator
Explore more in Health, Fitness, Nutrition & Body.
Cite this tool
Zerdly. (2026). Kids Clothing Size Calculator. Retrieved from https://www.zerdly.com/tools/kids-clothing-size-calculator/
Tip: Enter any known values to calculate the remaining results.
Designed to run locally in your browser. Tool inputs are not intentionally stored by Zerdly unless stated otherwise.