How to Choose the Right Shoe Size: Buying Shoes Online
Measure Feet at Home and Find the Perfect Fit
Buying shoes online is easy until the box arrives and the fit is off. Too tight in the toes. Slipping at the heel. Fine when standing, painful after 20 minutes.
The fix starts before checkout. If you know your current foot length, width, and fit clues, you can read size charts with a lot more confidence. Here’s how to measure at home, check your current shoes, and figure out how to pick the right shoe size online without guessing.
The quick rule for buying shoes online
Don’t shop by the size you “usually wear” alone. Shop by your foot measurements plus the store’s size chart.
Shoe sizes can vary between styles because of shape, toe box, lining, sole thickness, and how the shoe is meant to fit. A pointed flat won’t feel like a sneaker in the same size. A sandal won’t fit like an ankle boot.
A good fit comes from three things:
Your foot length
Your foot width
The shoe’s shape and intended fit
Measure both feet, use the larger foot as your guide, and check the size chart in centimetres when possible. In Canada, many online shops use US sizing, but you may also see EU sizing or measurements in cm. The measurement is your best anchor.
How to measure your foot size accurately at home
You don’t need special equipment. A few basic items will do.
You’ll need:
Two sheets of paper larger than your feet
A pencil
A ruler or measuring tape with centimetres
Socks, if you’ll wear socks with the shoes
A flat wall
A hard floor
Avoid measuring on carpet. It can shift and make your measurement less accurate.
Step 1. Measure at the right time of day
Measure your feet in the afternoon or evening. Feet often swell a little during the day, especially after walking, standing, or warm weather.
If you measure first thing in the morning, you might pick a size that feels too snug later.
Wear the type of socks you plan to wear with the shoes. Thin socks for dress shoes. Thicker socks for boots or winter footwear.
Step 2. Place the paper against a wall
Put one sheet of paper on a hard floor with the short edge touching the wall. Tape it down if it slides.
Stand with your heel lightly touching the wall. Keep your weight evenly on both feet. Don’t sit while tracing, unless you’re measuring for a shoe style you mainly wear seated, which is rare.
Standing matters because your foot spreads under body weight.
Step 3. Trace your foot carefully
Hold the pencil straight up and down. Trace around your foot without angling the pencil inward or outward.
If you tilt the pencil, the outline can come out too small or too large.
Repeat with the other foot. Most people have one foot that’s slightly bigger. That’s normal.
Step 4. Measure the length
Find the longest point from heel to toe. It may be your big toe, or it may be the second toe.
Measure from the back of the heel to that longest toe mark. Write the number down in centimetres.
For example:
Left foot length
Right foot length
Use the longer foot when checking a size chart.
Step 5. Measure the width
Find the widest part of your foot. This is usually across the ball of the foot, near the base of the toes.
Measure straight across that section. Write it down in centimetres.
Width matters a lot. If the length is right but the width is wrong, the shoe still won’t feel good.
Step 6. Add a little room at the front
Your toes need space. For most closed-toe shoes, aim for about 0.5 to 1 cm of space between your longest toe and the front of the shoe.
You may want more room for hiking-style footwear or thick socks. You may want slightly less in open sandals, depending on the design. Still, your toes should never hang over the edge.
Step 7. Compare your measurement to the size chart
Now check the shop’s size guide. Match your foot length in cm to the size shown.
If you’re between sizes, think about the shoe type:
Shoe style | If you’re between sizes |
Sneakers and casual shoes | The larger size may feel better, especially with socks |
Boots | The larger size often works better with thicker socks |
Sandals | Check the footbed length and strap placement |
Pointed-toe shoes | The larger size may help, but width and shape matter |
Slip-ons | Be careful sizing up too much, since the heel may slip |
If the store gives fit notes, read them. Phrases like “runs small,” “narrow fit,” or “roomy toe box” can make the difference.
Do feet change size with age?
Yes, feet can change size over time. They don’t usually “grow” the way they did in childhood, but their shape, length, and width can change.
A few common reasons include:
Arches can flatten over time
The arches in your feet can lower gradually. When that happens, the foot may spread and become longer or wider.
That can make an old size feel tight, even if your weight and shoe style haven’t changed.
Ligaments and soft tissue can change
Feet are held together by bones, ligaments, tendons, and muscles. Over time, those structures can become less firm. This may let the foot spread more when standing.
This is one reason someone may wear a different size at 45 than they did at 25.
Weight changes can affect foot shape
Weight changes can affect how much the foot spreads under pressure. This doesn’t mean everyone’s size changes with weight, but it can be a factor.
Pregnancy can change foot size
Pregnancy can affect ligaments and fluid retention. Some people notice wider or longer feet during or after pregnancy. For some, the change is temporary. For others, their old shoes may never feel the same again.
Swelling can change fit during the day
Heat, long flights, salty meals, standing for hours, or certain health conditions can cause swelling. That can make shoes feel tighter than usual.
If swelling is frequent, painful, or one-sided, it’s best to check with a healthcare professional. This post is general fit advice, not medical guidance.
The takeaway is simple. Don’t assume your shoe size is fixed forever. Re-measure every so often, especially after major body changes, pregnancy, injury, or a long stretch of uncomfortable shoes.
How to tell if your current shoe size is correct
Your current shoes can tell you a lot. Put on a pair you wear often and check the fit while standing.
Your toes should have room to move
You should be able to wiggle your toes. They shouldn’t feel squeezed, curled, or pressed into the front.
For closed-toe shoes, check for a small gap in front of your longest toe. If your toe touches the end while standing, the shoe is likely too short.
The widest part of your foot should match the widest part of the shoe
This is a big one. If the ball of your foot sits behind or ahead of the shoe’s widest point, the shoe may bend in the wrong place.
That can cause rubbing, pinching, and pressure.
Your heel should feel secure
A small amount of movement can be normal, especially in new shoes. But your heel shouldn’t pop out with every step.
If you’re gripping with your toes to keep the shoe on, it’s not the right fit.
The sides shouldn’t bulge or gap
Look at your foot from above.
If your foot spills over the sole or pushes hard against the sides, the shoe may be too narrow. If there are large gaps around the sides, it may be too wide or too big.
Pressure marks are a clue
Take the shoes off after wearing them for a while. Red marks don’t always mean disaster, but deep marks, numbness, or sore spots are warning signs.
Check these areas:
Little toes
Big toe joint
Back of heel
Top of foot
Arch area
Ankles, especially with boots
The shoe should feel good while walking, not just standing
Stand, then walk around. Try stairs if safe. Your foot changes position as you move.
A shoe that feels okay for 10 seconds may rub after 10 minutes.
Can you measure your foot online?
Yes, you can measure your foot with online tools, but they still need careful setup.
Most online foot measuring methods use one of these:
A printable size guide
A phone camera scanning tool
A measurement form where you enter length and width
A size chart based on cm measurements
The most reliable “online” method is still simple. Measure your feet at home in centimetres, then enter or compare those numbers online.
What you need for printable measuring guides
If a shop offers a printable guide, you’ll need:
A printer
Standard paper
A ruler to check the print scale
A hard floor
Socks you plan to wear
Before using it, check the scale marker on the printout. Many guides include a test line or box. Measure that with a ruler. If the printed scale is off, the whole guide is off.
Make sure printer settings are set to actual size or 100%. Don’t use “fit to page.”
What you need for camera-based tools
Some online tools use a phone camera to estimate size. These can be helpful, but lighting, angle, and setup matter.
Use:
A phone with a working camera
Bright, even light
A flat floor
Bare feet or thin socks, depending on instructions
Any reference object the tool asks for
Follow the instructions exactly. If the tool asks for a certain angle or distance, don’t rush it.
Even then, use the result as a guide, not a guarantee. Your preferred fit, foot width, and shoe style still matter.
When online tools are most useful
Online measuring tools work best when you already know what type of fit you like.
For example, if your measurement puts you between two sizes and you know you prefer extra toe room, that helps you choose. If you have wide feet, high arches, bunions, or swelling, check width and shape just as closely as length.
How to choose between two sizes
Being between sizes is common. Don’t panic. Use a few fit clues.
Choose the larger size when:
Your longer foot is near the top end of the smaller size
You’ll wear thick socks
The shoe has a pointed or narrow toe
Your feet swell during the day
Reviews or fit notes say the style runs small
Choose the smaller size when:
The shoe is open-toe and the larger size leaves too much extra sole
The shoe is a slip-on and your heel lifts too much
The material is likely to relax with wear
Your measurement sits at the low end of the larger size
Be careful with the idea that shoes will “stretch out.” Some materials soften, but length rarely changes much. A shoe that hurts from the start is a risky buy.
A simple online shoe size checklist
Before you buy, run through this quick list.
Measure both feet in the evening
Use centimetres for length and width
Compare the larger foot to the size chart
Read the fit notes for the exact style
Think about socks, swelling, and toe shape
Check the return or exchange policy
Don’t rely only on your usual size
If you’re replacing an old pair, check where it wore down. Heavy wear on the outer edge, stretched sides, or crushed toe areas can hint that the fit wasn’t right.
Frequently asked questions
Should I size up when buying shoes online?
Size up if your measurement is close to the upper end of the size chart, the shoe looks narrow, or you’ll wear thicker socks. Don’t size up automatically. Too much extra room can cause slipping and rubbing.
Is foot length or width more important?
Both matter. Length keeps your toes from hitting the front. Width keeps the sides from pinching. If one is wrong, the shoe won’t feel right.
How often should I measure my feet?
Measure at least once a year if you shop online often. Also measure after pregnancy, weight changes, injury, or if your shoes start feeling tight for no clear reason.
What if one foot is bigger than the other?
Fit the larger foot. For the smaller foot, you can often improve fit with socks, insoles, heel grips, or adjustable straps, depending on the shoe.
Can I use my usual size from another pair?
Use it as a starting point only. Check the current pair’s fit, then compare your actual foot measurements to the size chart for the shoes you’re buying.
Find the fit that feels right
The best online shoe purchase starts with a tape measure, not a guess. Measure both feet, use the larger one, check length and width, and match those numbers to the shop’s size guide. Then think about the shoe style, socks, and how your feet feel at the end of the day.
If you’re ready to shop with your measurements in hand, browse footwear in CAD and compare each style to the fit you need.
A good shoe should feel secure, comfortable, and easy to walk in. When you know your measurements, finding that fit online gets a whole lot easier.
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