Buying shoes online hinges on one simple thing: knowing the true size and shape of the foot you will wear the shoe on. Small differences in length, width or the time of day you measure can turn a comfortable pair into a painful one. Measure in centimetres, wear the socks you will use with the shoes, and capture both length and width every time.
This guide gives a step-by-step list of the most reliable checks for preparing a measurement you can trust, explains the tools people use, points out the common mistakes and the shoppers who need to size differently, and shows the exact next steps to take so a measurement actually helps when completing an online order. Also read the fine print of return policies before committing to a single pair.
Priority checklist: the measurements that matter
This section contains six ordered checks. Follow them in sequence: order here implies what to check first and how often each factor matters. Each heading states the rule first, then why it matters and how to do it. Every point stands alone so a shopper who jumps to one heading will still get a complete answer.
Stand and press lightly
Measure while standing and bearing weight on the foot being measured. When the foot takes weight it spreads and elongates; seated measurements usually underestimate required length and can lead to shoes that pinch when walking. Pressing lightly with the hand keeps the heel seated against the wall or measuring surface and gives a repeatable point for the heel-to-toe length.
Measure in centimetres
Record the foot length and the widest point in centimetres rather than relying on size labels. Most international size charts convert from centimetres and an exact centimetre value is what retailers use to map between regional systems. Keep the measurement to the nearest half centimetre; when in doubt, choose the larger number rather than estimating downwards.
Wear the socks you will use
Measure with the same thickness of sock you plan to wear with the shoes. A thin dress sock and a thick training sock will change required internal volume by noticeable amounts. If buying multiple types of shoes, record two measurements: one for thin socks and one for thicker socks used during training or cold weather.
Measure at the end of the day
Take measurements in the late afternoon or evening when the feet are at their largest. Feet swell slightly with activity and heat during the day; a pair that fits in the morning can feel tight after a day of walking. Measuring at the end of the day gives a safe margin and reduces the chance of ordering a pair that will pinch under normal use.
Measure both feet and use the larger value
Always measure left and right separately and use the larger length and width when choosing a size. Most people have a small but consistent size difference between feet; ordering for the larger foot prevents one shoe from being tight while the other fits. Keep a written record of each foot so repeat purchases match earlier pairs.
Check the return policy before you buy
Confirm the retailer’s return window, who pays return postage and whether they accept returns after a single wear. Even with precise measurements, last shapes and internal volume differ between brands and models and a flexible return policy is part of the cost of buying online. If returns are limited or final-sale, prefer retailers that publish exact internal length in centimetres rather than only regional size labels.
Common measuring tools and when to use them
There are a few reliable methods to capture foot dimensions and each suits a particular need. Choose by the detail required and the equipment available at home or at a shop.
- Ruler or tape: A simple straight ruler or a soft tape is fine for length and is the easiest at home when paired with a wall and a hard floor.
- Tracing on paper: Use a piece of paper against a wall, step on it and trace the outline; this makes measuring both length and maximum width straightforward and repeatable.
- Brannock device: The standard measuring instrument used in many shoe stores for both length and width, and especially useful when shops are open.
- Foot scanner apps or kiosks: These can produce a 3D profile and help with brands that publish last profiles, but their results vary by provider and should be cross-checked with a simple centimetre length.
The tracing method and the Brannock device each have strengths: tracing records the footprint and width visually, while the Brannock device is designed to measure both length and standardised width grades. Where available, use a Brannock device to confirm home measurements in centimetres.
Table: comparing measurement methods
| Method | Ease at home | Length precision | Width information |
|---|---|---|---|
| Ruler or tape | High | Good | Limited |
| Paper tracing | High | Good | Good |
| Brannock device | Low (shop required) | Very good | Very good |
| 3D scanner/app | Variable | Variable | Variable |
Where shoppers commonly go wrong
The most frequent errors are avoidable and repeatable. People measure in the morning, forget to wear match socks, rely on a single foot, or assume that a single regional size translates unchanged across brands. Another frequent mistake is treating the internal length label as an absolute guarantee; lasts differ by maker and older shoes may have stretched.
Also check how width is expressed by the retailer. In some systems width is a separate grade (letters or numbers); in others width is folded into model-specific fit notes. If the shoe brand is known for a narrow or wide last, use that as a tiebreaker after centimetre measurements rather than instead of them. Keep written centimetre measurements and compare them to the retailer’s published internal length table where available.
Who should measure differently
Beginners need a simple, conservative approach: measure at the end of the day, use the thicker sock you intend to wear for active use, and select the larger foot’s measurement. Experienced shoppers and people who already own pairs from a specific brand should keep a log of the internal lengths that fit them in centimetres for each brand and last. That log lets them skip redundant measurements when re-ordering the same model type.
People with irregular foot shapes, medical conditions, or significant differences between left and right should prefer in-person fitting when possible and consult brands that publish last profiles. For performance footwear—running, cycling shoes with stiff soles or cleats—measurements alone are necessary but not always sufficient; the interaction of sole stiffness and foot volume can still require trying on a pair before committing.
What to do next
Measure both feet in centimetres now, at the end of the day, wearing the socks intended for the purchase. Record length and maximum width for each foot and keep that note with previous fit records. Compare the larger foot’s centimetre values to the retailer’s internal length chart and to any brand notes on last width.
Before placing an order, re-check the return policy and the retailer’s instructions for returns: who pays, whether the shoes may be worn briefly, and the allowed timeframe. If returns are restrictive, prefer sellers who publish internal lengths in centimetres or offer free returns so a measured attempt does not become a final loss.
Frequently asked questions
How do I measure my foot in centimetres?
Stand on a hard floor with a piece of paper against a wall, wear the socks you will use, and press the heel to the wall. Mark the furthest point of the toes, measure heel-to-toe in centimetres, and repeat for the other foot.
When is the best time of day to measure feet?
Measure at the end of the day when feet are largest after normal activity. Measuring then gives a safer margin so shoes remain comfortable during walking or long wear.
What should I check about return policies?
Confirm the return window, who covers postage and whether lightly worn shoes are accepted for return. If returns are limited or final-sale, prefer sellers who publish internal length in centimetres.
