Understanding growth forecasts and uncertainty
Learn why children’s growth forecasts are useful but never exact, and how to use them when planning clothing and shoe sizes.
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A growth forecast is an estimate
Growth forecasts can be useful when planning children’s clothing and shoe sizes, especially before a new season. But they are not exact predictions.
A forecast uses current measurements and expected growth patterns to estimate a future measurement. For example, it may estimate whether a child who is 122 cm today is likely to need size 128 later in the season. A child may still grow faster or slower than expected.
Why growth varies
Population growth charts help describe typical growth patterns, but they do not predict one child’s exact future measurement.
- Age
- Genetics
- Nutrition
- Sleep
- Health
- Puberty timing
- Individual growth pattern
Growth is not evenly distributed
Children may have periods where they grow slowly and periods where they grow quickly. A child can stay in one clothing size for months, then suddenly need the next size.
This is especially common around growth spurts.
Why uncertainty matters for shopping
When buying clothes for immediate use, the current size is usually most important. When buying for a future season, uncertainty becomes more important.
For example, if you buy winter clothes in September, they may need to fit until February or March. If your child is already close to the upper end of a size, choosing the next size may be more practical.
How to interpret a size forecast
A useful size forecast should help you decide between options rather than pretend there is one perfect answer.
- Current best fit: 122
- Likely next-season size: 128
- If the garment is slim-fitting, consider sizing up
- If buying for immediate use, check the brand’s size chart
When to update your forecast
Update your child’s measurements whenever the forecast may no longer reflect current reality.
- Before buying seasonal clothing
- After a visible growth spurt
- Before buying shoes
- Every few months during fast-growth periods
- When clothes or shoes start feeling tight
Frequently asked questions
Is a growth forecast medical advice?
No. A WhatSizer forecast is a sizing planning estimate for clothing and shoes. It is not a medical assessment.
What makes a forecast more useful?
Recent measurements and a clear use case, such as buying for winter or summer, make a forecast more useful.