How to Find the Right Shoe Size When Buying Online

Updated 6 November 2026 · Standard formula, shown below

Buying shoes online is convenient, but getting the wrong size is a common frustration. This guide walks you through a reliable method to measure your feet at home, interpret brand-specific sizing, and choose the right size with confidence—so you can avoid the hassle of returns and exchanges.

What You’ll Need

A piece of paper larger than your foot (e.g., printer paper)
A pencil or pen
A ruler or measuring tape (with cm and inches)
A wall or flat surface
A sock similar to the one you’ll wear with the shoes
Access to the brand’s size chart (usually on their website)

Step-by-Step

Measure your feet at the end of the day. Feet swell throughout the day, so measuring in the evening gives you the most accurate size for everyday wear.
Wear the socks you plan to use. If you’re buying running shoes, wear athletic socks; for dress shoes, wear dress socks. This adds a few millimeters that matter.
Trace your foot. Place the paper on a hard floor against a wall. Sit down and place your heel against the wall. Trace around your foot with the pencil held vertically. Do this for both feet—they are often different sizes.
Measure the length. Use the ruler to measure the distance from the heel to the longest toe (usually the big toe or second toe). Write down the measurement in both centimeters and inches.
Measure the width (optional but helpful). Wrap the measuring tape around the widest part of your foot (the ball) while standing. Note the circumference. Many brands offer width options (e.g., D, EE).
Use the brand’s size chart. Every brand has its own size chart. Find your foot length in centimeters on the chart and note the corresponding size. Do not assume your usual size works across brands.
Check the specific shoe’s size guide. Some shoes run small or large. Look for a note on the product page like “fits true to size” or “we recommend going up half a size.”
Consider the shoe type. Running shoes often need a thumb’s width of space at the toe (about 1 cm). Dress shoes are usually snugger. Hiking boots may need room for thicker socks.
Choose the size for your larger foot. If your left foot is 26.2 cm and your right is 26.5 cm, go with the size that fits 26.5 cm. You can always add an insole to the smaller foot.
Order two sizes if you’re unsure. Many online stores offer free returns. Ordering two sizes (e.g., 9 and 9.5) lets you try both at home and return the one that doesn’t fit.

Common Mistakes

Measuring in the morning: Feet are smaller in the morning; you’ll end up with shoes that feel tight by afternoon.
Ignoring width: Two people with the same foot length can have very different widths. A narrow foot in a wide shoe will slip; a wide foot in a narrow shoe will hurt.
Assuming all size 9s are the same: A size 9 in Nike may not equal a size 9 in Adidas or a size 9 in a dress shoe. Always check the brand’s chart.
Not measuring both feet: Most people have one foot larger than the other. Using the smaller foot as reference leads to a tight fit.
Measuring over a thick carpet: The soft surface makes your foot sink, giving a false measurement.
Forgetting about socks: Barefoot measurements are smaller; you’ll get shoes that are too tight with socks.

Tips

Print a paper size chart: Some brands offer printable foot-measuring devices. Use them for a quick check.
Read customer reviews: Look for comments like “I usually wear 8.5, but these fit best in 9″—they reveal real-world sizing.
Know your Brannock size: If you’ve been measured at a shoe store, note your Brannock size (the metal device). It’s a good baseline, but still check each brand.
Check the return policy before ordering: Make sure you can return or exchange easily if the size is wrong.
Consider the material: Leather stretches, synthetic materials don’t. If in doubt, go slightly tighter for leather, slightly looser for synthetics.
Use the “thumb test”: When trying on, there should be about a thumb’s width (1 cm) between your longest toe and the end of the shoe. This allows for foot movement and swelling.

Troubleshooting

Your measurement is between sizes: If your foot length is exactly between two sizes, choose the larger size if you prefer a roomier fit or the smaller if you prefer a snug fit. For running shoes, go larger.
The shoes arrive too tight: Try wearing them indoors with thin socks for a few hours. If they don’t stretch, you may need to exchange for a half size up.
The shoes arrive too loose: Try adding an insole or wearing thicker socks. If they still slip, exchange for a half size down.
One foot fits, the other doesn’t: This is normal. Use the larger foot as your guide. For the smaller foot, you can use a heel grip or an insole.
You can’t find a size chart: Contact customer service with your foot measurements in centimeters. They can recommend a size.

Frequently Asked Questions

How much space should I leave at the toe?

About a thumb’s width (1 cm) from your longest toe to the end of the shoe is ideal for most shoes. For dress shoes, half a thumb’s width is enough.

Should I order the same size as my usual shoe size?

Not necessarily. Sizes vary by brand and style. Always check the brand’s size chart and reviews. Your usual size is a starting point, not a guarantee.

What if my feet are different sizes?

Use the larger foot for sizing. You can add an insole or heel pad to the smaller foot to make it fit better.

Do I need to measure both feet?

Yes, because most people have one foot slightly larger. Always go with the larger measurement.

Can I use a ruler instead of a measuring tape?

Yes, a ruler works fine for length. For width, a flexible measuring tape is easier, but you can also use a string and then measure the string.

How often should I measure my feet?

At least once a year, especially if you’re an adult. Feet can change size due to weight, age, or pregnancy.

Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.