Buying shoes online starts with one simple fact: the number on a box is only useful if the measurement behind it is accurate. This guide explains how to measure feet in centimetres, why timing and socks matter, and which measuring method to trust for different situations.
Follow the steps here before clicking buy. The aim is to turn guesswork into a repeatable measurement that fits retailers’ size charts and makes returns avoidable.
How to decide what measurement you need
Deciding how to measure depends on what is being bought. Firm-structured boots and cleats need more attention to length and volume; flexible trainers tolerate a little room. Start by checking the retailer’s chart for centimetres rather than relying on a labelled size. If the shop lists only UK/US/EU sizes, convert by the centimetre figure: conversions vary between brands and between men’s and women’s lines.
Common mistakes buyers make
Shoppers often measure barefoot at night, ignore sock thickness, or use a ruler from memory. Those errors create a consistent bias: measured length that is too short. Another frequent error is measuring the wrong foot; most people have one foot slightly larger. Finally, ignoring the store’s return policy turns small measurement doubts into expensive decisions.
What differs for a beginner and an experienced buyer
A beginner should prioritise repeatability: measure twice, at the same time of day, with the same socks, and record the centimetre value. An experienced buyer will already know a brand’s last and may add width notes or preferred toe-room. Both benefit from keeping one measured centimetre value per foot and a brief note on the sock thickness used when measuring.
Measuring tools compared
Different tools suit different needs. The table below compares three practical approaches on accuracy, convenience and when to use them.
| Method | Accuracy | Convenience | Best for |
|---|---|---|---|
| Brannock device | High when used correctly | Requires access to device | Boots, cleats and frequent buyers |
| Ruler or tape on floor | Good if careful | Easy at home with one assistant | General footwear purchases |
| Printable chart | Variable; depends on printer scaling | Most convenient but check print scale | Quick checks and casual trainers |
For people unfamiliar with a Brannock device, it is worth trying in a shop or asking a friend; the device measures length and width together. If a Brannock device is unavailable, a taped ruler on a hard floor gives a robust centimetre measure when done with care.
Length in centimetres
Measure the maximum heel-to-toe length in centimetres; that is the primary figure retailers use for conversion. Stand with weight on the foot while measuring, because an unloaded foot reads shorter. Record the longer foot’s centimetre value and use that as the buying reference.
Match socks
Measure wearing the same thickness of socks intended for the shoes. A thin match sock versus a thick training sock changes the internal fit. Note the sock type in the measurement record so the same conditions can be reproduced for future purchases.
Time of day
Measure in the afternoon or evening when feet are naturally at their largest. Feet typically swell slightly during the day; measuring first thing returns a smaller figure and increases the risk that shoes will feel tight after a few hours of wear.
Foot volume and width
Length alone does not guarantee fit. If feet are narrow or wide, add a width note alongside the centimetre length. Certain brand lines are known for their cut: some football boot ranges run narrow while some trainer labels have roomier lasts. Use the width note to cross-reference a brand’s typical cut on community fit guides or product pages.
Measure twice
Take two independent measurements, ideally with a short break between them. If they differ, take a third. Consistent values show a reliable procedure; a large spread indicates the method needs correcting — check sock thickness, stance and the measuring tool.
Check return policies
Always confirm the retailer’s returns and exchange rules for footwear. A clear free return window reduces the cost of a conservative purchase when measurement uncertainty remains. Note whether returns require the original box, tags, or a hygiene sticker to be intact.
Quick checklist before buying
- Measure in centimetres: Record the longer foot to the nearest millimetre if possible.
- Socks matched: Use the same thickness you will wear with the shoes.
- Time of day: Measure later in the day when feet are largest.
- Repeat: Take measurements twice and store the result.
- Return policy: Confirm returns or exchanges before purchase.
What to do next
Take the measurement now, record the centimetre values for both feet and note the sock type. Compare that centimetre figure against the retailer’s chart, prioritising the brand’s own conversions rather than a generic chart. If in doubt, choose the option that matches the longer foot and the intended sock thickness, and keep returns in mind as a safety net.
For a one-time high-stakes purchase — structured boots or expensive cleats — consider visiting a shop for a professional measure or asking to try the brand’s typical last in person before completing the online order.
Frequently asked questions
How do I measure foot length in centimetres?
Stand with full weight on the foot and place heel against a vertical surface. Measure the longest heel-to-toe point in centimetres, record the longer foot and repeat the measurement to confirm it.
Which socks should be worn when measuring?
Wear the same thickness of socks intended for use with the shoes, whether thin match socks or thicker trainers. Note the sock type with the centimetre measurement so future purchases match the same conditions.
What if two feet measure differently?
Use the larger centimetre measurement as the buying reference. Also add a width note if one foot appears significantly wider, and check the retailer’s return policy before finalising the purchase.
