Online Shoe Size Guide: Find Your Shoe Size When Buying Online

Buying shoes online means skipping the one thing that used to make sizing easy — actually trying them on. That's not a small trade-off. Get it wrong and you're stuck with a pair that pinches at the toe or slips at the heel, and depending on the seller's return policy, fixing that mistake can be expensive or simply not possible.

Here at Marcello Sarto, since every pair is made to order, getting your size right the first time matters even more than it would with off-the-shelf shoes. This online shoe size guide walks through exactly how to measure your feet, find your shoe size, and avoid the most common sizing mistakes.

Step 1: Measure Your Feet Properly (Don't Guess From Memory)

Most people assume they know their shoe size because it's what they've always bought — but foot size can shift slightly over the years, and sizing isn't standardized the same way across every brand or country. A fresh measurement takes five minutes and removes the guesswork.

What you'll need: a piece of paper larger than your foot, a pen, and a ruler or tape measure.

How to do it:

1. Place the paper on a hard floor, against a wall
2. Stand on the paper with your heel touching the wall, wearing the type of socks you'd normally wear with dress shoes
3. Mark the paper at the tip of your longest toe (this isn't always the big toe)
4. Measure the distance from the wall edge to your mark in centimeters or inches
5. Repeat for both feet — most people have one foot slightly larger than the other, and you should size for the larger one

Do this in the evening if possible — feet swell slightly over the course of a day, so an evening measurement gives you a more realistic sense of your true size for all-day wear.

Step 2: Use the Measurement to Find Your Shoe Size

Once you have your foot length, compare it with the brand's size chart rather than relying on memory alone. A proper shoe size conversion should be based on foot length, not just the size label you usually buy.

What this means practically:

• Always check the specific brand's size chart rather than assuming your usual size carries over
• Pay attention to whether the chart is based on foot length, not just a generic size label
• If a brand's reviews or sizing notes mention running large or small, factor that in specifically

How do I know my foot size online?

Measure your foot length at home, then compare that number with the brand's size chart. If the chart uses inches or centimeters, match your measurement to the closest size and check any fit notes before ordering.

If you're between two sizes, use the chart as your starting point and then consider how the shoe is made and how you plan to wear it.

How do I know what size shoe to order online?

Start with an accurate foot measurement, match it to the brand's size chart, and then check whether the style runs large, small, narrow, or wide. If you're still unsure, contact the seller before ordering.

Step 3: Understand That Sizing Isn't Universal

This is where most online shoe-buying mistakes actually happen. A US size 10, UK size 9, and EU size 43 don't always convert perfectly across brands, because sizing standards and lasts (the mold a shoe is built around) vary. Two brands both labeled "size 10" can fit noticeably differently.

What this means practically:

• Always check the specific brand's size chart rather than assuming your usual size carries over
• Pay attention to whether the chart is based on foot length, not just a generic size label
• If a brand's reviews or sizing notes mention running large or small, factor that in specifically

Step 4: Account for the Shoe's Construction and Material

Different shoe styles fit differently even at the same labeled size:

• Handmade leather shoes (like ours) are typically built on a proper last that's true to the measurement provided — but leather does have some natural give as it breaks in, so a snug-but-not-tight fit at purchase is usually correct
• Suede has less stretch than smooth leather and tends to hold its original shape more rigidly
• Boots often benefit from slightly more room than a low-cut oxford, since your foot naturally shifts forward a bit inside a taller shoe
• Narrower or wider feet should look specifically for width options if a brand offers them, rather than sizing up or down to compensate — this usually creates a worse fit, not a better one

For styles like derby shoes, loafers, ankle boots, lace up shoes, wingtip shoes, and monk strap shoes, the silhouette and closure can also affect how secure the fit feels, so compare the style as well as the size chart.

Step 5: When In Doubt, Contact the Seller Before Ordering

This is the step most people skip, and it's the one that actually prevents mistakes. A quick message asking "I measure X cm, and I usually wear a size Y in [other brand] — what size would you recommend?" takes two minutes and can save you an entire ordering mistake, especially for handmade or made-to-order shoes where returns and exchanges may work differently than mass-market retail.

A note specific to made-to-order shoes: because each pair is crafted to the selected size rather than pulled from mass-produced stock, sizing mistakes are harder to fix after the fact than with a shoe that was already sitting in a warehouse. Taking the extra few minutes upfront to measure carefully and double-check against the size chart is genuinely worth it — it's the single best way to make sure your first pair fits the way it should.

A Quick Checklist Before You Order

• [ ] Measured both feet, used the larger measurement
• [ ] Checked the specific brand's size chart, not just your usual size
• [ ] Considered the shoe style (boots vs. low-cut, suede vs. leather)
• [ ] Reached out to the seller if genuinely unsure

Common Questions

What size shoe is equivalent to 7 inches?

It depends on the brand and sizing system, so there isn't one universal answer. Use a size chart that converts foot length in inches to the correct size, since shoe size labels can vary.

What is my shoe size by inches?

Measure your foot length in inches from heel to longest toe, then compare that number to the specific brand's size guide. The measurement itself is more reliable than guessing from your usual size.

What if I'm between two sizes?

For dress shoes and formal leather footwear, sizing down slightly is usually the safer call, since leather gives a bit with wear and a slightly loose formal shoe looks and feels sloppy in a way a slightly snug one doesn't.

Should I size up for thicker socks in winter?

Generally no — buy true to your measured size and adjust sock thickness instead. Sizing up to accommodate socks usually creates a shoe that's loose the rest of the year.

My foot measurement falls exactly between two sizes on the chart — what do I do?

Check if the brand offers half sizes. If not, and you're choosing between rounding up or down, factor in the shoe type: round down for formal leather shoes (which stretch slightly), round up for boots or anything you'll wear with thicker socks.

Does foot width matter as much as length?

Yes, though it's less commonly measured. If you know you have particularly narrow or wide feet, mention it when reaching out to a seller before ordering — it can meaningfully change which size actually fits best.

Before ordering, check our size chart and don't hesitate to reach out with your measurements if you're unsure — we're happy to help you get it right the first time. Browse the full collection once you've got your size sorted.