Do not turn a Nike size into a New Balance size without checking the model. Start by measuring both feet while standing, use the longer one, compare the official chart and check whether the shoe has the width and toe room your child needs.
| What to check | Nike | New Balance | SIZES advice |
|---|---|---|---|
| Length | Use the foot measurement to locate a size in the kids' guide | Check the kids' footwear guide and the current model | Measure in millimetres instead of copying the number |
| Reference foot | The measurement should represent the foot that needs more room | The guide recommends checking both feet and using the longer one | Measure both every time, if possible later in the day |
| Width | Review the last and the product details for the specific model | Width information may be available by category and model | A correct length cannot fix a narrow shape |
| Use | Running, school and lifestyle shoes may be built differently | Support and volume change between product families | Compare shoes for the same use, not just the logo |
| Room | Leave toe room without letting the foot slide forward | Confirm length, width and fit through movement | Test walking, jumping, bending and stairs |
What the official guides say
The official Nike kids' footwear guide starts from foot length and lets you use that measurement to locate a size in its chart. It is a reference for that purchase, not a rule that covers every sports or casual model.
The official New Balance kids' footwear guide explains how to measure and reminds shoppers to check both feet. Its general size and width guide adds information for interpreting width options when they are available for a product.
Official sources are the right starting point because charts can change and because one shoe family does not represent another. Save the foot measurement, then check the product page again whenever the model, season or intended use changes.
Why September starts with the foot, not the label
Children grow quickly, and a shoe that seemed fine at the end of term can feel short after the summer. Feet are not fixed numbers either: when weight is placed on them they spread slightly, and the sock changes the available space.
The useful question is therefore not what size the child always wears, but how long the foot is today and how that measurement fits the shoe. The box number is a translation inside a particular chart. When the brand or pattern changes, the translation needs to be checked again.
Measure while the child is standing with weight distributed across both feet. If possible, repeat the measurement later in the day, after some movement. Use the school or sports sock the child will wear. A measurement taken seated and barefoot can create false confidence.
How to measure both feet at home
Place a sheet of paper against a wall and ask the child to put the heel against it without curling the toes. Mark the furthest toe. Repeat with the other foot, then measure from the paper edge to each mark in millimetres. Do not round before comparing the two measurements.
Repeat the test if the child moves the heel, turns the foot inward or loads one side more than the other. You can make a second mark with the reference shoe nearby, but the paper should show the foot with the sock the child will use. Save both lengths and note which foot is longer.
The result is not the exact internal length of a shoe. The insole, toe box, materials and construction create the final space. The number gets you into the chart; the movement test confirms whether the whole shoe works.
Length and toe room
A kids' shoe needs room in front of the toes for walking and a little growth, but not so much that the foot slides and loses stability. The right amount depends on use, construction and toe shape. A flexible running shoe does not feel the same as a more structured school shoe.
Check that the toes can move and that the heel stays secure. If the foot travels forward while walking, the issue may be the closure or the width rather than length alone. If the toes touch the front or curl, there is not enough room even if the number looks familiar.
A finger-pressure test at the toe can be a useful clue, but it is not a substitute for removing the insole when the design allows it and standing on it. Length needs to be read together with the closure, heel, insole and movement.
Width matters as much as length
A foot can match a size length and still need more room around the ball of the foot. Pressure marks at the sides, crowded toes, difficulty getting the foot in or visibly tense seams all suggest that you should check the last.
New Balance publishes width information in its general guide and for selected product families. That does not mean every shoe offers the same width options, so check the current product details. With Nike, read the shape and model description in the same way: the brand name alone does not tell you the last.
Do not add length to solve a width problem. A longer shoe can let the heel move and make a child drag their feet. Look for a width, closure or model that distributes space more appropriately.
Running, school and everyday use are different
For running, the shoe should hold the foot without blocking it and allow a natural stride. Look at flex, heel security, lateral stability and room for the sports sock. A running shoe does not need to feel like a firm school trainer.
For school, easy fastening, durability, all-day comfort and room for a slightly thicker sock may matter more. A well-adjusted hook-and-loop closure can be more useful than a technical construction if the child dresses independently.
For everyday wear, consider what clothing accompanies the shoe and how much walking is involved. The same foot length can need a different reading when a model has a very round toe, rigid structure or thick insole. Compare equivalent uses between Nike and New Balance so the decision is fair.
Closure, heel and independence
Laces, elastic and hook-and-loop closures distribute pressure differently. A closure that loosens while running changes the fit even when the size is correct. Ask the child to walk, bend and climb a step. Check whether they can adjust the shoe and recognise when the heel is secure.
The heel should stay stable without rubbing. If you have to tighten the closure heavily to stop it slipping, there may be an issue with volume or shape. Check the sock and test both feet: they may not need exactly the same sensation even though the child wears one size.
What to do between two sizes
Start by identifying the measurement separating the options. If the smaller shoe is short, the decision may be clear. If length works but width is tight, sizing up can create too much toe room without solving the side pressure. If the heel moves in both, change the last or closure.
Reasonable growth matters, but it should not turn the shoe into a boat on the first day. Back to school needs immediate comfort and stability for walking, running and stairs. A purchase that only works in three months is not a useful September solution.
If the child is close to the limit, try the shoe later in the day with the usual sock. Observe both feet and decide around the longer one. Save why you chose the size so the next purchase has more context.
SIZES tip: save a complete note: “Nike, running model, larger foot 214 mm, sports sock, stable heel, comfortable room”. A measurement without context does not tell you what happened while running or after several hours.
How to compare Nike and New Balance without inventing an equivalence
Choose two models with the same purpose first. Then open both official charts and locate the foot length in the stated unit. Note whether each model gives width information, which closure it uses and how the toe shape or use is described.
Compare the experience, not just the number. A Nike running shoe and a New Balance lifestyle trainer may have similar chart conversions and feel different when the foot flexes. Two kids' models from the same brand can also use different patterns.
A good comparison ends with a physical test or a clear return policy. Walk indoors, take a few quick steps, check the heel and look at the toe area. If an online product page lacks useful information, lower your confidence in the conversion and choose a better-documented listing.
Common mistakes before buying
The first is copying last term's size without measuring again. The second is measuring only one foot. The third is adding a huge amount of room because growth feels unpredictable. It is also common to compare a sports shoe with a school shoe and blame the difference on the brand.
Another mistake is looking only at length. A foot can have space at the front and be compressed at the sides, or have the right width and still lose stability because the heel is not held. Insole, closure and material all belong in the decision.
Finally, do not turn one child's experience into a universal brand rule. Their feet, sock, activity and model matter. Save the reference for that child and measure again whenever one of those variables changes.
The five-minute movement test
With the usual sock, let the child walk, stop, turn, make a small jump and climb a step. Watch whether the heel stays, the toes remain free and the shoe bends where the foot bends. Do not rely only on how it feels while seated.
Ask where pressure appears and request a specific answer: front, side, instep or heel. Check the skin after a few minutes and make sure laces or hook-and-loop do not leave deep marks. A comfort detail the child can describe is useful sizing information.
How to use SIZES to save the reference
Save both foot lengths, the longer foot, the sock, the activity and the model's feel. A note such as “New Balance, school, 218 mm, hook-and-loop, comfortable width and secure heel” will help more than “size 35”. When the child grows, you will know which part of the decision can be repeated.
For more context, read how to choose kids' sandal size, see how to measure children's clothes at home and compare another trainer decision in Nike vs Adidas Kids or Decathlon vs Nike Kids.
Final recommendation
Nike and New Balance offer different guides and product families, but no label replaces measuring the foot. Use the longer foot as your starting point, check width and purpose, and confirm comfort through real movement.
Frequently asked questions
Do Nike and New Balance use the same kids' size?
Do not assume it. Equivalence depends on foot measurement, the chart and the specific model, as well as width and closure.
Should I measure both feet?
Yes. Measure both while standing and use the longer one as your reference. Repeat when the sock or use changes.
Should I size up because my child is growing?
Only when the measurement and movement test support it. Excess length can reduce stability and will not solve a width problem.
What if New Balance offers another width?
Check that the option exists for the current model and choose around the child's foot and the product chart, not a general brand rule.