Convert approximate shoe sizes between U.S., U.K., European, Japanese, Korean, and Mondopoint systems, or measure your foot and use foot length as the starting point. Brand sizing and shoe fit can vary.
Shoe Size Converter
Foot length in millimeters is the common reference point. Pick a mode below.
US men's and women's use different numbering sequences and are always listed separately below.
US
mm
mm
mm
The calculator uses the larger of the two measurements as the main sizing reference. It does not average them.
Width labels such as B, D, E, EE, Wide, and Extra Wide vary by brand and by men's and women's sizing. Use the manufacturer's width chart.
Place a sheet of paper on a hard floor against a wall.
Wear the type of socks you normally wear with the shoe.
Stand with your weight on the foot being measured.
Keep the heel against the wall where practical.
Mark the position of the longest toe on the paper.
Measure from the heel reference to the longest-toe mark.
Repeat for the other foot.
Use the longer measurement as the main sizing reference. Do not add extra length automatically; manufacturers build fit allowance into their own lasts and sizing.
Visual: Foot-Length Measurement
Foot length is the straight-line distance from the heel to the longest toe, measured while standing.
How foot length is measured
Reference Point
Description
Heel
Back edge of the foot, placed against the wall
Longest toe
Front-most point of the foot, usually the big toe or second toe
Foot length
Straight-line heel-to-toe measurement used as the sizing anchor
Shoe size conversion is not as exact as converting inches to centimeters or pounds to kilograms. Footwear sizing systems developed differently around the world, and the International Organization for Standardization recognizes this problem. ISO 19407:2023 provides conversion guidance for major footwear sizing systems and uses foot length as the logical starting point.
That is the best way to think about this shoe size converter: the labeled size is a reference, and the foot measurement is the anchor. Every value in this calculator is read from a local, foot-length-anchored reference model rather than a fixed rule that forces one system's number onto another.
Visual: Foot Length as a Common Anchor
US, UK, EU, Japanese, and Korean sizes are all read from the same underlying foot-length reference, in millimeters, rather than converted directly from one another.
Systems referenced from a common foot-length anchor
System
Anchored To
US Men's / US Women's
Foot length in millimeters
UK Adult
Foot length in millimeters
European (EU)
Foot length in millimeters
Japan (cm)
Foot length in millimeters
Korea (mm) / Mondopoint
Foot length in millimeters
Why Shoe Sizes Are Not Exact Conversions
A shoe labeled EU 40 is not produced by converting one universal mathematical US size. Factors include the shoe last, toe shape, brand grading, internal length, width, material, intended fit, and manufacturing tolerance. That is why two shoes with the same printed size can fit differently.
CalculateThisWay provides approximate cross-system references while keeping the underlying foot-length reference visible, instead of pretending that a size like US 9 equals EU 42 as an exact law of measurement for every shoe.
How Do I Measure My Foot for Shoe Size?
Place a sheet of paper on a hard surface. Wear the socks you normally expect to wear with the shoe. Stand normally so your weight is on the foot. Measure from the heel to the end of the longest toe.
Visual: Foot-Length Measurement
Heel-to-toe foot length, measured while standing, is the anchor this calculator uses for every system shown.
Foot-length measurement reference points
Point
Meaning
Heel
Starting reference against the wall
Longest toe
Ending reference, the front-most point of the foot
Repeat for the other foot. Many people have slightly different left and right foot lengths. Use the longer foot as the primary sizing reference.
Why Should I Measure Both Feet?
Feet are not always identical. For example, a left foot of 252 mm and a right foot of 255 mm is a common pattern. If a shoe is chosen based only on the 252 mm foot, the longer foot may feel cramped. This calculator therefore uses 255 mm, the larger measurement, as the main reference, and clearly labels it as the sizing reference length with the reason: larger foot used.
Visual: Both Feet
When both feet are measured, this calculator always uses the larger measurement for sizing. It never silently averages the two.
Both-feet example: left 252 mm, right 255 mm
Foot
Length
Used for Sizing
Left
252 mm
No
Right
255 mm
Yes, larger foot used
The smaller foot can often be accommodated through fit adjustments, but a shoe should not be too short for the longer foot.
What Is Mondopoint?
ISO 9407:2019 describes Mondopoint as a footwear sizing and marking system based on defined measurements of the foot the footwear is intended to fit. The system uses millimeter-based foot dimensions. A foot-length reference of 255 mm can therefore be represented using a Mondopoint-style length designation, which makes international comparisons easier to understand.
Visual: Mondopoint Length Reference
A measured foot length in millimeters maps directly to a Mondopoint-style length marking concept.
Mondopoint length reference example
Measured Foot Length
Mondopoint-Style Marking
255 mm
255
U.S. Men's vs. U.S. Women's Shoe Sizes
U.S. men's and women's footwear commonly use different number sequences. A popular rule of thumb says a women's size can be around 1.5 sizes above a men's size, but that relationship is not guaranteed across every manufacturer. This calculator uses the foot-length reference model rather than blindly applying women minus 1.5 equals men for every shoe. If you are cross-shopping men's and women's shoes, the specific brand's chart is the final reference.
U.S. to European Shoe Size
European sizes use a different numbering system, so U.S. 8 cannot be converted using a simple unit multiplier. The result also depends on whether the U.S. input is men's, women's, or youth. This converter asks for the exact input system before producing an EU reference, and keeps US Men's and US Women's as separate options.
European to U.S. Shoe Size
The same warning applies in reverse. An EU 40 may correspond to nearby U.S. sizes depending on the men's or women's system, the manufacturer, and the shoe design. This calculator returns an approximate reference and shows the associated foot-length reference whenever available.
U.K. vs. U.S. Shoe Sizes
U.K. and U.S. size numbering look similar but are not identical. Do not assume the same printed number means the same fit. A U.K. size entered here is converted using the foot-length reference model rather than simply relabeling it as the same U.S. number.
Japanese Shoe Sizes
Japanese retail sizes are often expressed in centimeters and are more visibly measurement-oriented than U.S. or European labels. That makes foot length especially useful when comparing Japanese sizing. Still, verify the specific brand chart, because fit allowance and available increments vary.
Korean Shoe Sizes
Korean footwear is often referenced using millimeter-based sizing. Values such as 240, 250, and 260 are much easier to interpret when compared directly with foot-length measurements. Again, the product's own size chart remains important.
What Shoe Size Is 25 cm?
Twenty-five centimeters equals 250 millimeters. This calculator compares that foot length against its reference model and shows nearby U.S., U.K., EU, Japan, Korea, and Mondopoint sizes. The interactive calculator above is the source of the current conversion; the number is not hardcoded separately in this paragraph.
Do I Need to Add Extra Length to My Foot Measurement?
Do not automatically add a fixed amount. Shoes need internal allowance for the toes and movement, but manufacturers account for this differently through last design, shoe type, intended use, and size grading. If a shoe company tells customers to add a specific amount, follow that brand's method. This calculator uses measured foot length as the anchor and lets the reference model account for normal sizing variation.
Do Running Shoes Fit Differently?
They can. Running shoes may be selected with more toe room than certain dress shoes, heels, or fashion footwear, and sports shoes also differ by model. A generic shoe converter cannot determine ideal performance-shoe fit, so use the manufacturer's fit advice for specialized footwear.
What About Shoe Width?
Width is another dimension of fit. A shoe can have enough length but still feel too narrow or too wide. Labels such as B, D, E, EE, and Wide are not globally universal, so this converter does not create one universal width conversion chart. If width matters, check the specific manufacturer.
Why Does the Same Shoe Size Fit Differently by Brand?
A printed size is not the actual shape of the inside of a shoe. Brands use different last shapes, toe boxes, heel shapes, materials, width grading, and internal allowances.
Visual: Size Conversion Is Approximate
Three brands can label a shoe with the same size number while the actual internal shape and fit differ slightly.
Same labeled size, different brands
Brand
Labeled Size
Actual Fit
Brand A
Size 9
Runs as labeled for that brand's last
Brand B
Size 9
Slightly roomier toe box
Brand C
Size 9
Slightly narrower, more tapered last
That is why measured foot length plus a specific product chart is usually more useful than relying only on the number printed on an old pair of shoes.
Should I Measure My Foot Sitting or Standing?
Standing is generally more representative for shoe fitting, because the foot bears body weight. Use the same measurement method each time. If mobility or balance makes standing measurement impractical, use a safe method or ask another person to help.
Children's Shoe Sizes
Children's sizing changes quickly as feet grow. This calculator provides an approximate US Big Kids and Youth reference only for a limited foot-length range, rather than merging toddler, little-kid, and big-kid charts together. For very young children's sizes, use the specific brand's current children's size chart.
Shoe Size Converter vs. Unit Converter
Use this Shoe Size Converter for US, UK, EU, Japan, Korea, and Mondopoint, because those are sizing systems, not ordinary units. Use the CalculateThisWay Unit Converter when you simply need inches to centimeters or centimeters to inches, and the Height Calculator when you need a person's height rather than a foot length.
The Bottom Line
A shoe size converter should not pretend that international sizing is perfectly standardized. The best process is to measure both feet, use the longer foot, compare foot length with approximate size-system references, and check the exact brand's chart before purchasing. CalculateThisWay makes that uncertainty visible rather than hiding it behind a falsely precise result.
Quick Reference Table
These rows come from the same local, foot-length-anchored reference model used by the calculator above. They are approximate references, not a guaranteed fit for any specific brand.
Foot Length
US Women's
US Men's
UK Adult
EU
Japan (cm)
Korea / Mondopoint (mm)
Worked Shoe Size Examples
The examples below are computed live in JavaScript by the same engine used by the calculator above, not typed in as fixed text, so they always match what the calculator itself would return for these foot lengths.
250 mm Foot Length
255 mm Foot Length
260 mm Foot Length
Round-Trip Consistency Check
Try It Yourself
A friend's right foot measures 258 mm (about 10.16 in).
Which approximate US Men's and US Women's references does this reference model return?
Which Calculator Do I Need?
Shoe Size Converter (this page)
I want an approximate shoe size reference across US, UK, EU, Japan, Korea, or Mondopoint, or I want to find a size from a measured foot length.
Pick the system you already know in Convert Shoe Size mode, enter the size, and the calculator maps it to a foot length in millimeters, then reads approximate references for the other systems from that same foot length.
How do I convert US shoe size to EU?
Choose US Men's or US Women's, enter the size, and the calculator shows an approximate EU reference, including a range such as between EU 40 and 40.5 when the result falls between standard EU sizes.
How do I convert EU shoe size to US?
Choose European as the input system and enter the EU size. The calculator returns approximate US Men's and US Women's references separately, since those two systems use different numbering.
Are U.S. men's and women's sizes the same?
No. U.S. men's and U.S. women's footwear use different number sequences for the same foot length, so this calculator always keeps them as two separate systems rather than one generic US size.
How do I convert women's shoe size to men's?
Enter the US Women's size in Convert Shoe Size mode. The calculator finds the corresponding foot length and reads the approximate US Men's reference from that same length, rather than applying one fixed offset.
Is women's size always men's plus 1.5?
No. A women's-size-equals-men's-plus-1.5 shortcut is commonly repeated and happens to be close for some brands, but it is not universal. This calculator uses a foot-length-anchored reference instead of applying that shortcut as a rule.
How do I convert U.K. to U.S. shoe size?
U.K. and U.S. numbers look similar but are not identical. Choose UK Adult, enter the size, and the calculator reads approximate US Men's and US Women's references from the matching foot length rather than reusing the same number.
Is EU shoe sizing the same for men and women?
The EU scale itself is a single numbering sequence, but the same EU number can sit at a different point relative to US men's and US women's sizing, so this calculator still reports separate US men's and women's references for a given EU size.
What shoe size is 25 cm?
A 25 cm (250 mm) foot length corresponds in this reference model to approximately US Women's 8, approximately US Men's 6.5, approximately UK 6, and approximately EU 39.5. These are approximate cross-system references, not a guaranteed fit.
What shoe size is 250 mm?
250 mm is the same foot length as 25 cm, so the same approximate references apply: approximately US Women's 8, US Men's 6.5, UK 6, and EU 39.5 in this reference model.
What shoe size is 26 cm?
A 26 cm (260 mm) foot length corresponds in this reference model to approximately US Women's 9, US Men's 7.5, UK 7, and EU 41.
How do I measure my foot?
Place a sheet of paper on a hard floor against a wall, wear the socks you would normally wear with the shoe, stand with your weight on the foot, and measure from the heel to the longest toe.
Should I measure both feet?
Yes. Many people have a slightly different left and right foot length, and this calculator's Both mode uses the larger of the two measurements as the main sizing reference rather than averaging them.
Which foot should I use?
Use the longer foot. If a shoe is sized to the shorter foot only, the longer foot may feel cramped, while a slightly larger shoe can often be adjusted for the smaller foot.
What is Mondopoint?
Mondopoint is a footwear sizing and marking system based on measurements of the foot the footwear is intended to fit, using millimeter-based foot length as its reference.
What does 255 Mondopoint mean?
A Mondopoint marking of 255 refers to an approximate 255 mm foot-length reference, which in this model corresponds to approximately US Men's 7, US Women's 8.5, UK 6.5, and a EU reference between 40 and 40.5.
How do Japanese shoe sizes work?
Japanese retail sizes are commonly expressed in centimeters and are more directly measurement-oriented than US, UK, or EU labels, though fit allowance still varies by brand.
How do Korean shoe sizes work?
Korean footwear is often referenced using millimeter-based sizing, such as 240, 250, or 260, which this calculator compares directly against measured foot length in millimeters.
Why do shoe sizes vary by brand?
Brands use different lasts, toe shapes, internal lengths, width grading, materials, and rounding choices, so a printed size is a brand's own labeling decision rather than a single universal measurement.
Is a shoe size conversion exact?
No. Shoe size conversions are approximate references, not an exact unit conversion like inches to centimeters, because sizing systems developed independently and manufacturers apply them differently.
Why am I two different sizes in two brands?
Two brands can label shoes built on different lasts with the same printed size, so the same number does not guarantee the same internal shape or length. Measured foot length plus the brand's own chart is more reliable.
Do running shoes fit differently?
They can. Running shoes are sometimes chosen with more toe room than dress shoes or fashion footwear, and fit also varies by model, so this general converter cannot determine ideal performance-shoe fit.
How much extra room should shoes have?
This calculator does not specify a fixed extra-room amount, because manufacturers already build their own allowance into lasts and sizing systems in different ways. Follow the brand's own fit guidance for a specific shoe.
Should I automatically add half an inch?
No. This calculator does not add a fixed amount such as half an inch to a measured foot length, since shoe manufacturers already account for fit allowance differently through their own last design and grading.
What about shoe width?
Width is a separate dimension of fit. This calculator accepts an optional width note but does not convert it, because width labels are not standardized the same way across brands.
What does D width mean?
Width labels such as B, D, E, EE, Wide, and Extra Wide vary by brand and by men's and women's sizing, so this calculator does not announce one universal width conversion. Use the manufacturer's width chart.
Can children's shoes use the same chart?
Only partly. This calculator includes a limited approximate US Big Kids and Youth reference for a narrow foot-length range. For very young children's sizes, use the specific brand's current children's size chart.
Does foot length change during the day?
Feet can swell slightly over the course of a day, so measuring consistently, such as standing and at a similar time of day, helps keep repeated measurements comparable.
Should I measure wearing socks?
Wear the type of socks you would normally wear with the shoe you are sizing, since sock thickness can make a small difference to a snug fit.
Is this converter based on ISO?
This calculator follows the general principle described by ISO 19407:2023 and ISO 9407:2019, that foot length is the logical basis for comparing sizing systems. It uses an independently constructed local reference model rather than reproducing ISO's own tables or text.
Where should I check before buying shoes online?
Check the specific retailer's or brand's own size chart for that exact shoe model before purchasing, since printed size alone does not guarantee fit.
Sources & Further Learning
ISO 19407:2023 Footwear, Sizing, Conversion of sizing systems. International Organization for Standardization (iso.org).
ISO 9407:2019 Footwear sizing, Mondopoint system of sizing and marking. International Organization for Standardization (iso.org).
NIST: Reference for exact inch-to-millimeter and inch-to-centimeter conversion (1 inch equals exactly 25.4 mm) - nist.gov/pml/owm/metric-si/si-units
Methodology & Limitations
Foot length in millimeters is used as the internal anchor for every system shown, following the general principle described by ISO 19407:2023.
This calculator uses an independently constructed local reference model built from publicly documented consumer size-chart relationships. It does not reproduce ISO's own tables, formulas, or text, and it is not a substitute for a brand's own size chart.
US Men's and US Women's are always kept as separate systems and are never merged into one generic US sequence.
Results between standard sizes are shown as a range, such as between EU 40 and 40.5, rather than forced into a single value.
No universal men's-plus-1.5-equals-women's formula is used as the conversion algorithm; both systems are read independently from the foot-length anchor.
No universal shoe-width conversion is provided. Width is noted but not converted.
US Big Kids / Youth references are shown only for a limited foot-length range. Younger children's sizes are not covered; use the brand's own children's chart.
1 inch is treated as exactly 25.4 mm for all unit conversions in this calculator.
This calculator runs entirely with a local dataset. It does not scrape or call any manufacturer website at runtime.
This calculator provides approximate cross-system shoe size references built from an independently constructed, foot-length-anchored local model. It is not an official reproduction of ISO 19407:2023 or ISO 9407:2019, and it does not guarantee fit for any specific brand, last, or model. Manufacturers use different lasts, internal lengths, width systems, and rounding, so always check the specific brand's current size chart before purchasing.