FREE SHOE SIZE CALCULATOR

Find your true shoe size from one foot measurement.

Measure your foot length once, then instantly see your size across 35 brands — athletic staples like Nike and Adidas, running specialists like Hoka, Brooks and Saucony, hiking and boots from Keen, Timberland and Dr. Martens, and comfort brands like UGG, Crocs and Birkenstock — plus a generic international estimate. No account, no guesswork.

Start measuring
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STEP 1

Enter your foot length

Measure heel to longest toe (see the guide below), then enter it here in whichever unit is easiest.

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ShoeSizeIt — Result
Enter a foot length between 1 and 40.
Stand on a sheet of paper, mark your heel and longest toe, then measure the distance between the marks. Use your longer foot if the two differ.
Give each family member a name to keep their sizing history and growth chart separate.
BRAND CONVERTER

Already know your size in one brand?

Pick a brand and size you already own and we'll bridge it through foot length to show your size in every other brand we cover — no re-measuring required.

MEASUREMENT GUIDE

How to measure your foot length accurately

A shoe size is only as good as the measurement behind it. This takes about two minutes and just needs a piece of paper, a pencil, and a ruler or tape measure.

1
Tape paper to a hard floor

Carpet compresses under your heel and skews the measurement, so use a hard, flat surface, and tape the paper down so it can't slide while you stand on it.

2
Wear what you'll wear in the shoe

If you plan to wear the shoes with thick socks, measure with those socks on — sock thickness can shift a measurement by a few millimetres, enough to change your size.

3
Stand naturally, weight balanced

Stand on the paper with your full weight evenly balanced on the foot being measured, the way you'd stand normally — not on your toes. Feet flatten and spread slightly under load-bearing weight, so measuring while standing gives a truer size than measuring a foot held in the air.

4
Mark heel and longest toe

Have someone else mark the very back of your heel and the tip of your longest toe on the paper — it isn't always the big toe. A pen held straight down keeps the marks accurate.

5
Measure the distance between the marks

Use a ruler or tape measure to record the straight-line distance between the two marks. That's your foot length.

6
Repeat for both feet, use the longer one

Most people have one foot slightly longer than the other — sizing to the longer foot avoids a cramped fit.

Bonus tip: Measure again later in the day. Feet swell slightly over the course of a day, especially after standing or exercise. Measuring in the afternoon or evening gives a more realistic everyday size than a first-thing-in-the-morning measurement.

FREQUENTLY ASKED QUESTIONS

Common sizing questions

35 brands, grouped by what they make: athletic (Adidas, ASICS, New Balance, Nike, Puma, Reebok, Under Armour); running (Altra, Brooks, Hoka, Mizuno, On, Salomon, Saucony); hiking & outdoor (Columbia, Danner, Keen, LOWA, Merrell); boots (Blundstone, Dr. Martens, Red Wing, Timberland, UGG); casual & skate (Clarks, Converse, Skechers, Sperry, Steve Madden, TOMS, Vans); sandals & comfort (Birkenstock, Chaco, Crocs, Teva) — plus a generic international estimate. A few have quirks worth knowing: Crocs uses whole sizes only, Birkenstock is sized natively in EU rather than US/UK, Blundstone's half sizes add width rather than length, and Dr. Martens' UK-to-US labeling varies by model — each is flagged directly in that brand's result.

Stand on a piece of paper on a hard floor, have someone mark the back of your heel and your longest toe, then measure the straight-line distance between the marks — that's your foot length. It takes about two minutes with just paper, a pencil, and a ruler; the full step-by-step Measurement Guide below covers socks, weight distribution, and a few details that affect accuracy.

Run a tape measure around the widest part of your forefoot, across the ball of the foot, keeping your weight on it. Width matters because length alone will not tell you whether a shoe pinches — and a shoe that is the right length but too narrow often gets mistaken for one that is too small. Full instructions are on the measuring guide, and you can enter the measurement in the calculator above to get a width letter.

Each brand designs its own "last" — the foot-shaped mold a shoe is built around — and publishes its own size chart against that last. Two brands can label very different foot lengths with the same size number. That's why this calculator works from your actual foot length in centimeters and looks it up against each brand's own published chart, rather than assuming a size number carries over between brands.

Each system was standardized independently and doesn't share a common reference point. EU sizing, for example, is based on the "Paris point," where each whole size represents about 6.67mm of length — a completely different basis than the US or UK scales. None of them convert to each other with one fixed offset, which is exactly why this calculator starts from your actual foot length instead of a size number in any single system.

It depends on the brand, which is the whole reason this site exists. A 26 cm foot is a men's US 8 in Nike and most other brands — but a US 7 in Birkenstock and a US 9 in Reebok, Keen and Steve Madden. That is the same foot spanning two full sizes depending on whose shoe it is. Rather than memorise a conversion, enter 26 in the calculator above and it will show you every brand at once. As a rough starting point, a men's US size is roughly your foot length in centimetres minus 18, but that approximation breaks down at the edges of the range and between brands.

The usual advice is to subtract 1.5, and for many brands that is right — but not for all, and the exceptions are why it matters. Where a brand publishes a women's chart separate from its men's one, the gap at the same foot length is a full 1 size for Adidas, Chaco, Columbia, New Balance, Nike, Red Wing, Sperry, TOMS and UGG; a full 2 sizes for Birkenstock and Blundstone; and half a size for LOWA. For Danner it is not even a fixed number — the gap shifts across their own size run. So a blanket "subtract 1.5" is wrong for at least 13 of the brands here. For the 16 brands that publish no separate women's chart, this site applies the conventional 1.5 offset to the brand's own measured foot lengths, so treat those women's numbers as a sound convention rather than something the brand printed. Teva publishes men's and women's charts that share no common foot length, so no offset applies at all. Either way, converting through foot length rather than between size numbers is the reliable method — which is what the calculator does.

By default we round up to the next chart size, since a slightly roomier shoe is usually more comfortable than a cramped one — this matters most for kids' shoes, since feet keep growing between purchases. If you'd rather see the closest size instead (up or down), switch "If I'm between sizes" to "Use the closest size" in the calculator.

About a thumb's width — very roughly 1 cm — between your longest toe and the end of the shoe is the common guideline, and a little more for running shoes, since feet swell and slide forward on descents. Be careful not to add that room twice, though: some brands already build it into their published chart and some do not. Altra tells you to add 0.5 cm to your measurement before reading their chart, Mizuno suggests 1 to 1.5 cm, while LOWA states it has already included 15 mm for you. Where a brand gives its own instruction, this site shows it in that brand's fit notes rather than silently folding it into the numbers.

Yes — if you already know your size in one brand, the Brand Converter section lets you enter it and see the equivalent size across every other brand we cover, bridged through foot length rather than just matching size numbers, which don't line up reliably between brands. If you haven't measured your foot yet, the main calculator above does the same thing more directly.

Yes. Children's sizing uses its own scale (commonly shown as C for toddler sizes and Y for older kids' sizes) that doesn't continue directly from adult numbering, and the switch from kids' to adult sizing happens at a different point for different brands. Select "Children" as the category before calculating and we'll show sizes on the correct kids' scale rather than an adult one.

Every chart is checked against the brand's own published size guide, or against multiple independent retailer transcriptions of it when the brand's page can't be read directly. Even so, a size chart is a starting point, not a guarantee — fit still varies by shoe model, materials, and width, so treat the result as your best starting size rather than a certainty.

Length and width are two different measurements. New Balance publishes a full numeric width chart (2A narrow through 6E extra-wide), so we match your measured forefoot width directly against their real chart. ASICS, Skechers, Vans, and Converse also publish their own named width options (like ASICS's Narrow/Standard/Wide/Extra Wide or Vans's Wide Fit), so we match your measurement to whichever of their real options is closest. For brands that don't publish width data at all, we show a general industry-standard estimate instead, clearly labeled as an estimate rather than a brand-specific figure.

Yes, completely free, with no account or sign-up required. The site is supported by advertising rather than a paywall or subscription.

Your measurements, history, and preferences are stored only in your own browser's local storage — nothing is sent to a server. Clearing your browser data or using the "Clear" button in the history panel removes it. See the Privacy Policy for details.
ABOUT SHOESIZEIT

A sizing tool built around your actual foot, not a guess

Most shoe size charts ask you to already know your size in a system you may not use — then hope the conversion holds. ShoeSizeIt starts from the one measurement that doesn't change from brand to brand: your foot length. Enter it once, and we look it up against a generic international estimate or a specific manufacturer's own published chart, across 35 brands spanning athletic shoes, running, boots, and sandals.

The site keeps a light footprint on purpose: your measurements and history stay in your browser rather than on a server, it works offline after your first visit, and it's built to be fast on any device. It's a reference tool, not a fitting room — always confirm sizing against the specific shoe model when it matters, especially for narrow or wide feet.