How to Measure Feet for Trainers at Home: UK Length & Width Guide

The most reliable way to measure your feet for trainers at home is to measure both feet while standing, using the socks you plan to wear, then record length and width separately. For a repeatable length check, place your heel against a wall and use a hard-backed book to mark your longest toe. Use the larger foot measurement with the exact brand’s current size chart.

Your old shoe size is useful context, but it is not a permanent identity. Trainers from different brands and models can use different lasts, toe shapes and sizing maps. A fresh measurement gives you a physical starting point; the product chart and indoor fit test finish the decision.

How do I measure my feet for trainers at home?

Stand on a hard, flat floor with one heel gently against a wall, mark or measure the longest toe, and repeat for the other foot. Then measure the widest part of each forefoot and keep the length and width figures as separate notes. Do not wrap a tape around the foot and call that width: circumference, or girth, is a different measurement.

1. Measure later in the day if possible, when feet may be fuller after normal activity.
2. Wear the socks intended for the trainers.
3. Measure both feet with your weight evenly distributed.
4. Use the longer foot for length and the wider foot for width.
5. Match the results to the exact manufacturer chart, not a random conversion table.
6. Check toe clearance, heel hold, side pressure and flex indoors before wearing the pair outside.

What you need to measure your feet

The wall-and-book method for foot length

The wall-and-book method reduces the pencil-angle problem that can make a tracing inconsistent, but it is not a guarantee of perfect accuracy. The book, your heel position and your longest-toe position still need to be set carefully.

Step 1: prepare the wall and floor

Choose a flat wall without a thick skirting board pushing your heel forwards. Put a sheet of paper on the hard floor with one edge touching the wall. If the paper moves, tape it down. Keep a ruler, book and pen within reach.

Step 2: stand naturally

Wear the socks you expect to use with the trainers. Stand upright with your weight balanced and your feet roughly shoulder-width apart. Do not pull your toes back or push them into the floor. A helper makes the next step easier because you can remain still.

Step 3: mark the longest toe

Keep your heel gently against the wall. Place the hard-backed book on the paper with its edge square to the wall, then slide it carefully towards the longest toe until it just meets the toe. Do not crush the toe or lean forwards. Mark the book’s edge, then step away and measure from the wall edge to the mark.

Step 4: repeat on the other foot

Repeat the process for the second foot. The big toe is not always the longest toe, so measure to whichever toe reaches furthest. Record each result in millimeters or centimeters to the nearest millimeter you can reproduce.

If you do not have a book: the tracing method

Trace each foot on paper while standing, keeping the pen or pencil vertical rather than angled under the foot. Mark the back of the heel and the furthest toe, then measure a straight line between those points after stepping off the paper. Ask someone else to trace if possible; twisting your body to look down can move the foot and change the outline.

Do not treat a single tracing as a laboratory result. If the second attempt differs noticeably, check that the paper did not move, your heel stayed in the same place and the pen was held upright. Correct the setup and measure again instead of averaging a weak attempt with a better one.

How to measure foot width for trainers

Measure flat forefoot width across the widest part of the foot, usually around the joints behind the big and little toes. On a tracing, place the ruler across the two widest side points and record the straight distance. Do not measure across the toe tips, across the arch or around the ankle.

Width is not the same as shoe size. A longer trainer may feel less tight at the sides, but it can also leave too much space at the toe and allow the heel to lift. If side pressure appears while the measured length looks suitable, compare a wider or differently shaped model before automatically adding length. If you consistently feel pinching along the outer edge of your foot, use our trainer width diagnostic to check whether you need a wider sole platform.

Should you measure ball girth as well?

Ball girth is an optional advanced measurement for people who repeatedly struggle with forefoot or instep volume. It is the circumference around the ball of the foot, passing around the joints of the big and little toes. Use a soft tape without squeezing the foot, and measure both sides while standing.

SATRA identifies joint girth and foot breadth as important footwear-fitting dimensions, while a Brannock device also assesses length, arch length and width. Most online trainer charts do not publish a direct ball-girth conversion, so use the number to describe your foot to a fitter or compare models—not to invent a universal UK width letter.

A foot can look reasonably narrow on paper and still need more space over the instep. That is why length, flat width, ball girth and volume are related but not interchangeable.

Your at-home foot-measurement card

Write the numbers down rather than relying on memory. A record makes it easier to compare a new ASICS, Saucony or other trainer chart later.

What do the numbers mean?

Foot length is the straight distance from the back of the heel to the longest toe. Flat width is the side-to-side distance across the widest forefoot. Volume is the three-dimensional room over and around the foot, including the instep. The shoe’s last controls how those dimensions are arranged inside the trainer.

This distinction matters because a shoe can match your length and still feel tight at the little-toe joint, under the laces or around the heel. A measurement card tells you what to investigate; it does not replace trying the exact model.

What is a UK shoe size in centimetres?

There is no single centimetre-to-UK conversion that fits every trainer brand. The table below is an example of how a current New Balance men’s/unisex chart maps its own length column to UK sizes. It is useful for understanding chart structure, not for choosing an ASICS, Saucony, Nike or other model without checking that brand’s chart.

New Balance labels this as a brand chart, not a universal law. Nike also warns that the CM value printed on its shoes and boxes is different from foot length. When a chart offers a “Foot Length” row, match your measured foot to that row; do not assume the CM/JP label on a box is the same thing.

How much extra room should trainers have?

As a general rule, aim for 10–15 mm (roughly one thumb’s width) of space between your longest toe and the end of the trainer cavity. This is a practical fit check, not a reason to add length blindly. Do not add the allowance twice: first check whether the brand’s chart uses raw standing foot length or internal shoe dimensions before adjusting your target size. ASICS’ running-shoe measuring instructions tell shoppers to add approximately 1–1.5 cm before matching its chart, but that is guidance for the ASICS method and running use—not a universal formula for every trainer.

For everyday trainers, use the chart first and then check the result while standing and walking. Your longest toe should not repeatedly strike the front, and your foot should not slide forwards because the shoe is excessively long. Our five-point trainer fit test covers toe clearance, width, heel hold, instep pressure and flex.

How to use your measurement with a brand chart

1. Open the exact product page. Confirm whether the size selector is men’s, women’s, unisex or another system.
2. Find the chart’s measurement label. Look for “foot length” or “heel-to-toe,” and distinguish it from a box CM/JP label.
3. Use the larger foot length. If the right foot is 26.4 cm and the left is 26.1 cm, begin with the 26.4 cm measurement.
4. Compare width separately. A length match does not prove that the forefoot or instep will be comfortable.
5. Check the model’s fit notes. Technical overlays, padded linings and a structured heel can alter the usable space.
6. Test indoors. Walk, turn, stop and stand in the socks you measured with while the order remains returnable.

For ASICS and Saucony pairs, use the current manufacturer information for the exact model. The YIODesigner Sneaker Size & Fit Guide gives general UK, US, EU and centimetre context, but it does not override a model-specific chart.

What if your measurement falls between two sizes?

If your foot sits between two chart rows, compare the larger size first unless the product page gives different advice. New Balance gives this general recommendation because a short shoe cannot be made longer. However, a larger size that creates obvious heel slip is not a successful solution; the model may have the wrong width, heel shape or volume for your foot.

Do not size up simply because the sides feel tight if there is already generous toe room. That usually means you are trying to solve width with length. Compare a roomier shape or a listed wide option where available.

Common home-measuring mistakes

• measuring while sitting instead of standing with weight on the foot;
• measuring only one foot;
• using a soft surface or allowing the paper to slide;
• holding the pencil at an angle or pressing it into the foot;
• measuring to the big toe when another toe is longer;
• measuring width across the toe tips rather than the forefoot joints;
• wrapping a tape around the foot and treating circumference as flat width;
• rounding the measurement before reading the brand chart;
• adding toe allowance even though the chart has already accounted for it;
• assuming one brand’s UK, EU or CM mapping applies to another.

How to check the trainer after measuring

Measurement gets you to a sensible starting size. Fit decides whether the shoe works. Try both trainers indoors on a clean floor and check:

Frequently asked questions

Should I measure my feet barefoot or with socks?

Measure with the socks you expect to wear in the trainers. If you will wear thin sports socks, use those; if you will wear thick socks, include them in the measurement setup. Barefoot measurement is appropriate only when the footwear will actually be worn barefoot.

Should I measure both feet?

Yes. Use the longer foot for length and note the wider foot separately. Small left-right differences are common, and a too-short shoe cannot be corrected by adjusting the smaller foot.

How do I measure foot width with a tape?

For flat width, use a ruler across the widest forefoot points; for ball girth, use a soft tape around the metatarsal joints. These are different measurements. Do not pull the tape tight or use girth as a universal width conversion.

Is foot length the same as shoe length?

No. Your foot measurement is not the trainer’s internal length. The shoe needs usable toe room, and each brand explains its chart differently. Follow the chart’s stated foot-length or heel-to-toe guidance instead of trying to make the two numbers identical.

What should I do if I am between trainer sizes?

Compare the larger size first when the product gives no contrary advice, then check heel hold. If the larger pair slips badly while the smaller pair is short, the model’s shape may be wrong for your foot rather than the size simply being undecided.

Can a foot measurement tell me whether a trainer will fit?

It improves your starting point but cannot predict every part of fit. A chart cannot show exactly how a heel counter, overlay, lining or instep will feel in motion. That is why an indoor walk test remains important.

When should I get measured professionally?

Seek professional help when fit problems persist, your feet have changed after an injury or health issue, or you need specialist width or orthotic advice. An online measurement guide is not a diagnosis or substitute for clinical fitting.

Before ordering from YIODesigner

Keep your measurement card with the product details you are comparing. Start with the live size selector and model-specific notes, then use the YIODesigner Size & Fit Guide for general UK, US, EU and centimetre context.

Keep labels, packaging and soles in their original condition while checking the pair indoors, and read the YIODesigner returns policy before wearing new trainers outside.

A measured foot is a better starting point than a remembered size, but the best trainer is the one that also passes the walking fit test.

Sources and verification

This guide combines current manufacturer and technical fitting guidance with YIODesigner’s practical buying framework. It does not claim that YIODesigner has measured the internal dimensions of any model unless a documented measurement is published.

• ASICS — How to Measure Your Shoe Size
• Nike UK — Men’s Footwear Size Chart and Foot-Length Guidance
• New Balance — Size and Width Guide
• Clarks UK — At-Home Length and Width Measurement
• Brannock Device — Instructions and Fitting Tips
• SATRA — Global Foot Dimensions and Footwear Measurements
• YIODesigner — Sneaker Size and Fit Guide