Foot size, measured with your phone

Measure your foot with your phone

A sheet of A4 or US Letter is the ruler. Stand on it against a wall, take one photo, and get your foot length, width and size. No app, no sign-up: it’s measured on your phone, and the photo is never uploaded.

Take the photo

Measuring
  1. Paper against the wall, short edge touching it.
  2. Heel pressed to the wall, no gap, foot straight along the sheet, bare feet or dark socks. The length is measured from the wall.
  3. Phone straight above your foot, all four corners of the paper in the picture. See a good and a bad photo.
My paper

Measured on this device. The photo is never uploaded or saved.

How it works

Three steps, one sheet of paper.

  1. A sheet of paper on a wooden floor, its short edge pushed up against the skirting board.touching the wall

    01

    Paper against the wall

    Put a sheet of A4 or US Letter paper on the floor, short edge touching the wall.

  2. A foot in a dark sock standing on the sheet, heel against the wall, toes pointing along the paper.262 mmno gap

    02

    Heel pressed to the wall

    Stand on the sheet in the socks you’ll wear, heel touching the wall and your foot straight along the paper.

  3. A phone screen showing the photo to take: the whole sheet seen from above with the foot on it and floor all round.4 corners in view ✓

    03

    One photo from above

    Hold your phone over your toes so all four corners of the paper are in the picture.

A good photo, and one that won’t measure

Rendered examples, made the same way as the photos we test the measuring on.

A good photo: the whole sheet in view against the wall, the foot on it with the heel at the wall, taken from above.
Good. All four corners in view, heel against the wall, phone above the foot.
A photo that won’t measure: taken too close and off to one side, so the paper’s right-hand corners are cut off.
Won’t measure. Too close and off to one side: the paper’s right-hand corners are out of the picture.

Two things the photo can’t check for you

The length runs from the wall along the paper, so it’s right only if your heel touches the wall and your foot points straight along the sheet. In the photo the leg hides the heel, so check these before you take it.

Side view: the foot on the sheet with the back of the heel pressed against the skirting board.no gap✓ Right
Heel touching the wall
Side view: the foot on the sheet with a gap of about a centimetre between the heel and the skirting board.10 mm gap✗ Wrong size
A gap behind the heel The gap is added to your length: 4 mm (⅙ inch) can be half a size too big.
From above: the foot pointing straight down the middle of the sheet.✓ Right
Foot straight along the sheet
From above: the foot turned at an angle across the sheet.12°✗ Wrong size
Foot turned on the sheet The length is taken along the paper, so a turned foot measures short: 10° can be half a size too small.

Rather not use the camera? Type your foot length or print the foot ruler.

What you get from one photo

Length
Heel to the tip of the longest toe, to the millimetre, with its ± from the photo.
Width
Across the ball of the foot, and whether that’s narrow, regular or wide for your size.
Your size
In US, UK, EU, Japan and Mondopoint, your country’s first, and on each brand’s own chart.
Both feet
Measure the second foot and you’re sized for the longer one.

How accurate is it?

The paper does the hard part: its corners tell the measuring how the photo is tilted and how big a millimetre is, so the photo is flattened to a true top-down view before the foot is measured. On 314 test photos of adult feet of known length, rendered through phone camera models (lens, tilt, light, socks, floors), the median error was 0.19 mm and 95% were within 0.63 mm; width was within 0.36 mm at the median, and children’s feet 0.14 mm (122 photos). A US half size is 4.2 mm of foot, so on the test photos the error is a small part of a size. Real feet and real photos vary more, which is why your result shows its own ±.

When a photo can’t be measured well (a corner out of frame, the paper curled, too dark), it says why and asks for another rather than guessing. How we work out your size.

No app to install

It runs in your phone’s browser, on iPhone and Android. Add it to your home screen if you like: it opens like an app and keeps working offline. On a laptop, use a photo you’ve taken, or scan the code it shows to carry on on your phone.

Your photo stays on your phone

The photo is measured on your device and never sent anywhere or saved. Only the numbers stay, and only if you choose to save them on this device.

Measuring a child’s foot

Choose “A child’s foot” (or open the kids’ measure): kneel beside them, cup the back of the heel against the wall with your hand off the top of the foot, and take the photo. The result shows kids’ sizes and their band.

Questions

Is there an app to measure my foot size?

This page is the app: it runs in your phone’s browser, so there’s nothing to install or sign up for. You can add it to your home screen, and the measuring works offline once it has loaded.

Can my phone measure my foot without paper?

Not reliably from one photo: the camera can’t tell how far away the foot is, so it can’t tell its size. A sheet of A4 or US Letter is a ruler of known size in the same picture; that’s what makes the measurement possible.

Does it work on iPhone and Android?

Yes, in the browser on both. It’s tested in emulation of iPhone Safari (including versions before 16.4) and of mid-range and low-end Android phones. On a laptop, use a photo you’ve taken. You can always type your foot length in the calculator instead.

How accurate is it?

On 314 test photos of feet of known length, rendered the way phone cameras take them, the median error was 0.19 mm and 95% were within 0.63 mm. Your result shows its own ± from the photo. Real photos depend on the sheet lying flat and your heel touching the wall.

Is it free?

Yes. No account, no app, no sign-up.