Three things to remember
- 1Numeric sizes usually track reference height; month and T sizes are only rough ranges.
- 2The most reliable method is to measure a well-fitting garment: body length, chest width, waist width and inseam.
- 3When buying across brands, keep the original size as labelled instead of forcing everything onto one scale.
Common kids' size quick reference
The table below is an entry point for reading labels, not a guarantee for any particular brand. Your child's build, the cut, the stretch of the fabric and how they like clothes to fit all affect the choice.
| Common numeric size | Common month / T size | Reference height | Check again when buying |
|---|---|---|---|
| 60–70 | 0–6M | About 55–70 cm | Bodysuit crotch length and nappy room |
| 70–80 | 6–12M | About 65–80 cm | Shoulder width, cuffs and head opening |
| 80–90 | 12–24M | About 75–90 cm | Body length, rise and room to move |
| 90–100 | 2T–3T | About 85–100 cm | Waist, inseam and whether nappies are still worn |
| 100–110 | 3T–4T | About 95–110 cm | Chest width, shoulder seam and sleeve length |
| 110–120 | 4T–5T | About 105–120 cm | Actual body length and the brand's cut |
More reliable than measuring your child: use a well-fitting garment as the benchmark
- 1
Pick a well-fitting garment of the same kind
Top against top, dress against dress, trousers against trousers. Lengths across different categories are not comparable.
- 2
Lay it flat and measure the key points
For tops, measure body length and chest width at the underarm; for trousers, waist width, rise and inseam; for dresses, also check shoulder width and skirt length.
- 3
Compare against the garment measurements the brand publishes
Check whether they list flat garment measurements or body measurements, and watch for whether chest width needs doubling.
- 4
Leave sensible room for the season
Wearing it now and wearing it in six months are different questions. Estimate how long it will be worn, then allow for layer thickness and whether the fabric shrinks.
Different categories, different numbers to watch
| Category | Measure first | Common mistake |
|---|---|---|
| Tops / outerwear | Chest width, body length, sleeve length | Going by height alone and forgetting layer thickness |
| Trousers | Waist width, rise, inseam | An elastic waist that is still too tight, or too short a rise |
| Dresses | Shoulder width, chest width, skirt length | The width fits but the skirt length is not what you expected |
| Bodysuits | Shoulder-to-crotch length, head opening | The body fits but the poppers will not close |
| Hats / shoes and socks | Head circumference / foot length | Choosing by age alone instead of centimetres |
How should sizes be recorded so you can find them later?
When filing, keep the size as the label writes it — 90, 2T, 12–18M — rather than rewriting everything into an age you have guessed. Where you need more, use your own tags such as "runs small", "long cut" or "good for layering".
Whenever you notice something now fits or has become too small, mark it "wear soon" or "for sale". That is far more reliable than trying to predict your child's future height, and it gives the seasonal review something concrete to act on.
A five-second check before buying online
- Which season is this for?
- Does the brand's chart give body measurements or flat garment measurements?
- What does a well-fitting garment of the same kind actually measure?
- Is the fabric stretchy, will it be layered over something thick, or will it shrink in the wash?
- If the size is uncertain, will the seller provide measured photos?
Frequently asked questions
Common questions
What age is a kids' size 90?
It commonly lands somewhere around 1–2 years, but brands vary a lot. Read 90 as a pointer to roughly the 90 cm height band, and still go by the brand's size chart and the garment's measurements.
Are 2T and 90 the same?
At most they may land in a similar range; they are not interchangeable. The waist, hip and rise of a 2T can differ noticeably from one brand's 90 to another's.
Should I size up?
Not always. Outerwear can allow room for layers, but a neckline, shoulder seam, rise or shoe that is too big also affects movement and safety. Go by the measurements and the season you expect it to be worn.
Turn the method into a wardrobe you can search
The free plan holds 50 garments. Start with the one thing you most want to deal with today — there is no need to sort everything at once.