How to Measure Your Feet for Running Shoes (and Get the Right Fit)

Most runners know their shoe size, but when was the last time you actually measured your feet? Chances are it was years ago, probably while shopping for school shoes in a physical store. Since then, you've likely sized up as you’ve grown or experienced discomfort, until settling into the size you have "always been.

However, our feet continue to change shape over time, and running shoe sizing is not always identical to everyday footwear. Choosing your size based on guesswork, and getting it just slightly wrong, can be the main culprit behind painful blisters and unsightly black toenails.

Measuring your feet accurately takes about 5 mins and can be done easily at home. 

You will need:

• A sheet of A4 paper

• A pencil or pen 

• A ruler or tape measure 

• A wall and a hard floor surface (avoid carpet, as your heel can sink and skew the measurement)

• Socks you usually run in

Preparing to measure your feet

Before you start measuring, follow these essential rules to get the most accurate results

• Measure in the evening. Feet naturally swell by up to half a size over the course of a day (and while exercise) due to heat and activity. Prolonged standing causes gravity to pull fluid down into your lower limbs, while heat causes your blood vessels to widen. Measuring later in the day prevents you from buying shoes that feel way too tight after just a few miles.

• Wear your running socks. Never measure bare feet. Always wear the socks you intend to run in as the thickness of a technical sock adds noticeable volume.

• Measure both feet. It is completely normal for one foot to be slightly longer or wider than the other. Always use the measurement of your larger foot when choosing your size.

• Stand up. Never measure your feet while sitting down. The foot spreads out under body weight meaning that taking the reading seated gives you a much shorter and narrower result.

How to measure your foot length at home

For the length we suggest using a wall as a fixed reference point, this gives you a much better measurement than trying to trace around foot

Step-by-step instructions

1. Set up your paper. Tape your sheet of paper flat on a hard floor (tile, wood, or vinyl) flush against the bottom of a smooth wall.

2. Position your foot. Stand with your heel lightly touching the wall. Be sure to distribute your weight evenly across both feet.

3. Mark the longest point of your foot. With your pen or pencil make a mark paper straight against the longest part of your foot. Note: For many runners, this is the big toe, but for some this can be the second toe.

4. Measure the length. Step off the paper and measure in centimetres from the mark of the longest point to the edge of the paper where your heel met the wall. This is your foot length.

5. Repeat for your other foot. It is completely normal for one foot to be longer than the other. Record both measurements and use the largest measurement to determine your size.

What to do with your measurement 

Running shoes should be roughly half a size larger than your everyday shoes. When looking at the chart below, use this practical rule: add 0.5 cm to your measured foot length. This extra space accounts for toe splay upon impact, natural forward movement when running downhill, and foot swelling.

UK running shoe size reference charts

Match your measured foot length + 0.5 cm to the charts below to find your starting size.

Men's running shoe size chart

Women's running shoe size chart

Note: Sizing can vary slightly between manufacturers, so it's always worth checking specific size guides when ordering from a brand you haven’t used before.

How to measure your foot width

Length is only half the picture. A shoe that is the right length but wrong width can cause rubbing, hot spots, and painful pinching. This section is not just for those with wider feet, it's equally vital for runners with narrow feet who often assume a standard fitting will work for them.

Step-by-step instructions

1. Trace your foot. Place your foot back on your sheet of paper, and while standing carefully trace around your foot, paying extra attention to the sides and forefoot.

2. Find the widest part. This is typically across the ball of the foot, the area just behind your toes.

3. Measure across. Measure straight across this widest point in centimetres.

4. Compare to the charts: Use the table below to see where your measurement sits

Most running shoes are manufactured in a standard D (men's) or B (women's) width by default. However, many top brands like New Balance, Brooks, and ASICS offer wide alternatives.

Running shoe width chart

How to check the fit once your running shoes arrive

Measurements give you a great starting point but the true verdict happens when the shoes are on your feet. A good running shoe should feel comfortable straight out of the box, do not rely on a “break-in period” to fix a poor fit

Step-by-step instructions
Lace up comfortably and while standing work through these four checks:

1. Toebox (length check) While standing press your thumb down horizontally in front of your longest toe. There should be roughly a thumbnail's width of space between your longest toe and the end of the shoe. If your toes are touching the front your shoes are too small, and you should go up half a size .If there is considerably more than a full thumb's width of space, try sizing down.

2. Forefoot & (width check) Both the little toe and the big toe are not being pressed painfully inwards, there should be minimal contact with the side seam. If the upper is visibly stretching or bulging at the widest part of your foot, you need a wider fitting

3. Midfoot. The shoe should feel secure across the arch and midfoot, with no pinching or pressure. If the upper fabric is bunching or gathering, the shoe is likely too wide or too high in volume for your foot shape.

4. Heel. Walk around and try lifting your heels off the insoles. There should be minimal movement. Heel slipping is one of the most common causes of blisters on longer runs, and it almost always means the shoe is either too large or needs a different lacing technique.

Lace check

Once laced, look down at the two lines of eyelets on either side of the tongue:

• Parallel lines:  A balanced, proper fit.

• Eyelets pulled very close together: The shoe is too wide.

• Eyelets pulled far apart (forming a very wide 'V'): The shoe is too narrow.

Still feeling uncomfortable?

If you've followed these steps and the sizing feels right, but you're still experiencing persistent blisters or inner foot pain, the issue might actually be down to the type of running shoe you have chosen and your gait, rather than the size.

How your foot moves through each stride—whether you overpronate or underpronate (supinate)—changes how your foot interacts with the cushioning and support features of a shoe.

You can assess your stride characteristics in just a few minutes using our Online Gait Analysis Tool to find the right shoe for you.

Alternatively, check out our dedicated guides on underpronation and overpronation to make sure you're pairing your stride with the right shoe type.

The Best Support/Stability Running Shoes for Overpronation

The Best Running Shoes for Underpronation and Supination

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