Kids Innerwear: Size by Age, Fabric and What Children Need

Size by age, 1 to 12 years

The number on the label is the waist measurement in centimetres. The ages below are what that measurement usually corresponds to — but children of the same age vary by several centimetres, so treat age as a starting point and measure where you can.

Above size 80 you are into adult numbering, which runs to 100. Because the bloomer shape is the same all the way up, an older child and an adult can wear the same style in different numbers. The full chart, both units, is on our size guide.

How to measure a child

1. Find the natural waist — above the hip bone, at the crease that forms when the child bends to one side.
2. Run a tape around it, level all the way, snug without pressing in.
3. Read the number in centimetres and round up to the next 0 or 5. A child measuring 62 cm takes size 65.

No measuring tape at home? A length of thread or a phone charging cable, marked where it meets and held against a school ruler, gives you the same number.

Bloomer or panty for girls?

For girls in a skirt or pinafore uniform, the bloomer — the longer-legged cotton shape — is the practical choice. The extra leg keeps coverage through sitting cross-legged on the floor, PE, running and the trip home, and it stops thigh rubbing on a hot afternoon. Under trousers or leggings, a shorter panty is fine.

This is why bloomers for girls are still the default in most Indian schools, and why our bloomer ranges — Sofie Bloomer and Everfine Bloomer — start at size 45 rather than at an adult size. For boys, the drawer is the usual shape instead: that is the Sofie Kids Drawer, a unisex cut in the same children's sizes. If you want to see the two shapes photographed together, our guide to bloomer vs panty shows both.

Fabric, and the three real complaints

100% cotton is the sensible daily choice for a school day in this climate — soft against the skin, and it moves moisture instead of trapping it. A cotton-rich blend costs a little less and holds shape slightly longer, but on a hot afternoon in a closed classroom the difference is felt immediately.

Beyond fabric, children complain about three things, consistently:

• A scratchy inner seam, usually at the inner thigh.
• A stiff label sewn inside the waistband.
• Elastic that digs in — nearly always a size problem rather than a design one.

All three are checkable in ten seconds before you buy, and all three are worth more attention than the print on the front. A child will tell you within a minute whether a garment is comfortable; that feedback beats anything on the packet.

How many pairs

Plan for the washing cycle rather than the week. For a child at school five days a week, seven to ten pairs is what works in most homes:

• Five for school days.
• Two for the weekend.
• Two or three spare for the wash, for a rainy week when nothing dries, and for the set the school asks you to keep in the bag.

Fewer than that and the same pairs are washed and worn constantly, which is what wears out elastic fastest. A slightly larger number of moderately priced pairs lasts longer over a year than a small rotation of expensive ones.

When to move up a size

Re-measure once a year, before the school year starts. Four centimetres of growth at the waist is a full size. Between annual checks, the garment tells you:

• The waistband leaves a deep mark after an hour, or rolls down.
• The leg opening rides up during play instead of staying put.
• The child starts adjusting it without being asked.

Any of those means the next size, not a different brand.

Washing so they last the year

• Cold or warm water, never hot. Heat is what kills elastic.
• Keep new dark colours away from whites for the first few washes.
• Dry in shade — strong sun fades dark colours and yellows white.
• Do not wring the waistband. Reshape it and hang it to dry.
• Replace when the elastic stops returning to shape. Washing cannot fix that, and sizing down to compensate makes it worse.

More detail in our cotton innerwear care guide, and everything specific to the school day in school innerwear for girls.

Buying: brands, shops and what to check

Children's innerwear is bought locally far more often than online, and the questions that matter are the same either way:

• Is the size printed on the garment? If not, you cannot re-order the same fit next year.
• Does the seller publish a size chart in centimetres? A brand that explains its numbering intends you to get the right size.
• Is it 100% cotton, and does the shop know? A shopkeeper who cannot answer is selling on price alone.
• Will the same colour and size exist in six months? Consistency between production lots is what separates a brand from a job lot.

Sofie Kids Drawer

Sofie Kids Drawer is our children's drawer: 100% cotton, the drawer shape rather than the bloomer, plain or striped, in sizes 45 to 80. The cut is unisex and it is most often bought for boys — girls in skirt uniforms are usually better served by a bloomer, and Sofie Bloomer and Everfine Bloomer both run from size 45. It is made in the same unit in Ammapalayam, Tiruppur as the adult ranges, on the same cotton — the difference is the size, not the quality of the fabric. Shops and distributors can ask us about the children's range directly.

Common questions

What size innerwear fits a 5 year old?

Size 60 usually suits a 5 to 6 year old — a 60 cm waist. Measure where you can, because waist size varies more than age suggests.

What size innerwear fits a 10 year old girl?

Size 75, a 75 cm waist, usually fits a 9 to 10 year old. An older or taller child may already be in 80.

Should girls wear bloomers or panties to school?

Bloomers under skirt and pinafore uniforms, because the longer leg keeps coverage through sitting, sports and play. Either shape works under trousers.

How many pairs of innerwear does a child need?

Seven to ten: five for school, two for the weekend, two or three spare for the wash.

Is cotton necessary for children's innerwear?

In this climate it is the sensible default. Cotton moves moisture away from the skin during a long school day, where a synthetic fabric traps it.

How often should children's innerwear be replaced?

When the elastic stops returning to shape, the fabric thins, or the child has grown about 4 cm at the waist. For most children that is once a year.