School Uniform Size Chart: How Sizes Work from LKG to 12

A school uniform size chart lists each size label against the body and garment measurements it covers, separately for every garment, from the smallest LKG size up to the largest senior size. A good chart uses one labelling system across the school, overlaps sensibly with neighbouring sizes, and is built around your own students rather than a generic adult chart. This guide explains how sizes work across classes and how to build a chart your parents and supplier can both use.

Why a size chart, not just class or age

It is tempting to order “Class 3 size” or “age 8 size”. Children in the same class vary widely in height and build, and a class-based size leaves the tallest and smallest students badly fitted. A size chart separates the size from the class: each child gets the size that fits, whatever class they are in.

Class still matters for planning, because it tells you which sizes are most common in each section. But the order should be placed by size, not by class.

How school sizes are usually labelled

Suppliers use different labelling systems. The common ones are:

• Numbered sizes, such as 18, 20, 22 and upwards, often tied to chest or length for shirts and to waist or length for bottoms.
• Age-based sizes, such as 3 to 4 years or 9 to 10 years, familiar to parents but less precise.
• Letter sizes, such as S, M, L and XL, more common for senior students and PT t-shirts.

Which system you use matters less than using one system consistently and printing it on the size label. Mixing systems between garments confuses parents. If PT t-shirts use letters and shirts use numbers, show both on the chart side by side.

What each garment’s size is based on

A size chart should have a separate section for each garment, because each one fits on different measurements.

Garment	Main measurements	Also check
Shirt	Chest, shirt length	Shoulder, sleeve length
Trousers	Waist, full length	Hip, inseam
Shorts	Waist, length	Hip
Skirt	Waist, length	Hip
Pinafore	Chest, full length	Shoulder strap length
Salwar kameez	Chest, kameez length	Salwar waist and length
PT t-shirt	Chest, length	Sleeve
Track pants	Waist, length	Hip

Ask your supplier which measurements their chart uses, and whether each measurement is a body measurement or a garment measurement. A body chest and a garment chest are different numbers, and mixing them up causes most sizing complaints.

How sizes progress from LKG to Class 12

Sizes do not grow in equal steps through the school.

• Pre-primary (LKG and UKG): small sizes, with elastic waists that cover a range of waist measurements.
• Primary: a run of sizes that move steadily with height.
• Middle school: the widest spread of sizes in a single class, as children grow at different times.
• Senior classes: adult-like proportions, with extra-large sizes needed for some students.

Expect the most size variety in Classes 6 to 9. That is where a size trial pays off. The kindergarten and play school uniform guide covers the smallest sizes in more detail.

Building your school’s own chart

You do not have to invent a chart from scratch. Start with your supplier’s standard chart and adapt it.

1. Ask for the supplier’s chart per garment, with each measurement clearly marked as body or garment.
2. Try sample garments on real students from a few classes, especially those at the edges of a size.
3. Note where sizes are too close or too far apart. If many students fall between two sizes, ask about adding an in-between size.
4. Agree any changes in writing, and ask the supplier to keep the agreed chart on record.
5. Share one final chart with parents and teachers, in the same format for every garment.

Here is a template layout you can adapt. It deliberately has no measurements filled in; your supplier provides the figures for its own patterns.

Size label	Usual classes	Chest	Shirt length	Sleeve
Size A	Pre-primary	(from supplier)	(from supplier)	(from supplier)
Size B	Pre-primary to Class 1
Size C	Classes 1 to 3
Size D	Classes 3 to 5

Make one table like this for each garment. The “usual classes” column helps teachers guide parents, but the measurements decide the size.

Allowing for growth

Uniforms bought in May or June have to fit until the next March. Build growth in sensibly:

• Choose the size that fits with a little room, not the tightest fit.
• Avoid going two sizes up; loose uniforms look untidy and can be unsafe for young children.
• Ask for a generous hem on trousers, skirts and pinafores so length can be let down.
• Elastic or adjustable waists cope better with a year of growth than fixed ones.

Agree a school-wide rule, such as “if between sizes, choose the larger”, and print it on the chart so every parent follows the same approach.

Common size chart mistakes

• Ordering by class or age instead of measurements.
• Mixing body and garment measurements on one chart.
• A different labelling system for each garment.
• No chart shared with parents before sizes are collected.
• Changing the chart each year, so reorders no longer match.

Once the chart is fixed, the next step is gathering every student’s size. Our guide on collecting student uniform sizes explains how to run that process, and mid-year school uniform reorders covers top-ups for new admissions.

Get a size chart with your quote

We make school uniforms to order at our unit in Konni, Pathanamthitta, Kerala, in every size from LKG to Class 12, including extra-large sizes for senior classes. We share a size chart with the quote, and for schools in our delivery area we can discuss a measurement visit. Once your sizes are confirmed, we keep them on record along with fabric and colour, so reorders follow the same sizing. The minimum order is 30 sets with mixed sizes allowed.

See our school uniforms page, then send your requirement on WhatsApp or through the quote form.