Foot length and international shoe scales
A UK 8.5 or EU 42 does not point to one fixed foot length: Continental sizing measures the shoe last in 6.67 mm Paris points, UK and US scales step in 8.47 mm barleycorns, and only Mondopoint measures the bare foot directly in millimetres.
Choose Adults or Children and select the shoe's toe allowance, then enter a bare-foot measurement or any retail size. Output separates bare-foot length from internal last length.
15 mm everyday fit
Reference example: EU 42 / UK 8.5 at 15 mm everyday allowance
Enter a foot length in cm or pick a size above to compute exact equivalents and build a shareable link.
CSS pixels vary in physical size from one display to another, so an uncalibrated screen ruler cannot measure millimetres accurately. Hold a standard bank or ID card (85.60 × 53.98 mm) against the outline below and adjust until the edges align.
Approximate size until calibrated with a bank card
Phone screens are typically 6–7 cm wide and under 16 cm tall, shorter than an adult foot. To measure a full foot reliably, trace heel-to-toe on A4 paper with a physical ruler.
Contradictory online size charts stem from two measurable causes: four incompatible unit steps and different toe allowances built into the shoe last.
Measures bare foot
Anchored at zero millimetres, it states actual foot length in millimetres (plus optional width). Size 265 literally means a 265 mm bare foot.
Measures the last
Each whole EU size adds two-thirds of a centimetre (6.67 mm) on the shoe last. ISO/TS 19407 adds a baseline allowance of two Paris points (13.33 mm).
Measures the last
Each whole UK or US size adds one-third of an inch (8.47 mm), and half sizes add 4.23 mm. US scales keep the same step while shifting the zero point.
An EU 42 always corresponds to a theoretical last length of 280 mm (28 cm), from 42 × 2/3 cm. The bare foot that fits inside that last changes with toe allowance: 270 mm (27 cm) in a snug dress shoe (10 mm allowance), 266.7 mm under the ISO/TS 19407 baseline (13.33 mm, Mondopoint 265), 265 mm (26.5 cm) for everyday closed-toe shoes (15 mm), and 260–262 mm in running shoes or winter boots (18–20 mm).
Under the same 15 mm everyday allowance, EU 38 has a 253.3 mm last for a 238.3 mm foot (240 mm ISO), EU 40 has a 266.7 mm last for a 251.7 mm foot (253.3 mm ISO), and EU 43 has a 286.7 mm last for a 271.7 mm foot (273.3 mm ISO). A measured 26.5 cm (265 mm) foot yields EU 41.75 on the ISO formula (41.5 snug, 42 everyday, 42.5 running).
Three EU Paris points equal 20.00 mm, whereas two and a half UK barleycorns equal 21.17 mm (the barleycorn-to-Paris-point ratio is exactly 1.27). Every 2.5 UK sizes, the two scales drift apart by 1.17 mm.
Because of that phase drift, adding 33 to a UK size happens to land close in the middle (UK 7 equals EU 40.1, rounded to 40), yet misses at both ends: UK 3 matches EU 35 (an offset of 32), while UK 12 climbs to EU 46.5 (an offset of 34.5).
| UK size | ISO foot (mm) | Exact EU (ISO) | Rounded EU | Naive UK + 33 | Actual gap (EU − UK) |
|---|---|---|---|---|---|
| 3 | 220.1 | 35.02 | 35 | 36 | +32.02 |
| 5 | 237.1 | 37.56 | 37.5 | 38 | +32.56 |
| 7 | 254.0 | 40.10 | 40 | 40 | +33.10 |
| 8 | 262.5 | 41.37 | 41.5 | 41 | +33.37 |
| 10 | 279.4 | 43.91 | 44 | 43 | +33.91 |
| 12 | 296.3 | 46.45 | 46.5 | 45 | +34.45 |
Both UK and US footwear systems advance in identical 8.47 mm (one-third inch) barleycorn steps, differing only in where size zero begins. US Men's sits one whole size above UK Adult (UK 8.5 equals US Men's 9.5).
US Women's uses two competing conventions: the Footwear Industries of America (FIA) and ISO/TS 19407 standard places US Women's two sizes above UK Adult (one size above US Men's), making UK 8.5 equal to US Women's 10.5. Many US retail brands instead use a +2.5 offset over UK (+1.5 over US Men's), labelling that same UK 8.5 as US Women's 11. Children's scales begin at UK 0 (with US Brannock starting 0.25 sizes higher, rounded to +0.5 in ISO tables or +1 in some retail charts) and run up to 13.5 before resetting to Adult size 1 — around a 20 cm foot (EU 32) on the US scale and half a size higher (EU 32.5) on the UK scale.
All 27 rows (whole and half sizes) are computed directly from ISO/TS 19407 formulas and the Paris point definition. Both ISO baseline foot length (13.3 mm allowance) and everyday foot length (15 mm allowance) are shown beside the fixed last length.
| EU | Last (mm) | ISO foot (cm) | 15 mm fit (cm) | Mondopoint | UK | US Men | US Women (FIA / common) |
|---|---|---|---|---|---|---|---|
| 35 | 233.3 | 22.00 | 21.83 | 220 | 3 | 4 | 5 / 5.5 |
| 35.5 | 236.7 | 22.33 | 22.17 | 225 | 3.5 | 4.5 | 5.5 / 6 |
| 36 | 240.0 | 22.67 | 22.50 | 225 | 4 | 5 | 6 / 6.5 |
| 36.5 | 243.3 | 23.00 | 22.83 | 230 | 4 | 5 | 6 / 6.5 |
| 37 | 246.7 | 23.33 | 23.17 | 235 | 4.5 | 5.5 | 6.5 / 7 |
| 37.5 | 250.0 | 23.67 | 23.50 | 235 | 5 | 6 | 7 / 7.5 |
| 38 | 253.3 | 24.00 | 23.83 | 240 | 5.5 | 6.5 | 7.5 / 8 |
| 38.5 | 256.7 | 24.33 | 24.17 | 245 | 5.5 | 6.5 | 7.5 / 8 |
| 39 | 260.0 | 24.67 | 24.50 | 245 | 6 | 7 | 8 / 8.5 |
| 39.5 | 263.3 | 25.00 | 24.83 | 250 | 6.5 | 7.5 | 8.5 / 9 |
| 40 | 266.7 | 25.33 | 25.17 | 255 | 7 | 8 | 9 / 9.5 |
| 40.5 | 270.0 | 25.67 | 25.50 | 255 | 7.5 | 8.5 | 9.5 / 10 |
| 41 | 273.3 | 26.00 | 25.83 | 260 | 7.5 | 8.5 | 9.5 / 10 |
| 41.5 | 276.7 | 26.33 | 26.17 | 265 | 8 | 9 | 10 / 10.5 |
| 42 | 280.0 | 26.67 | 26.50 | 265 | 8.5 | 9.5 | 10.5 / 11 |
| 42.5 | 283.3 | 27.00 | 26.83 | 270 | 9 | 10 | 11 / 11.5 |
| 43 | 286.7 | 27.33 | 27.17 | 275 | 9.5 | 10.5 | 11.5 / 12 |
| 43.5 | 290.0 | 27.67 | 27.50 | 275 | 9.5 | 10.5 | 11.5 / 12 |
| 44 | 293.3 | 28.00 | 27.83 | 280 | 10 | 11 | 12 / 12.5 |
| 44.5 | 296.7 | 28.33 | 28.17 | 285 | 10.5 | 11.5 | 12.5 / 13 |
| 45 | 300.0 | 28.67 | 28.50 | 285 | 11 | 12 | 13 / 13.5 |
| 45.5 | 303.3 | 29.00 | 28.83 | 290 | 11.5 | 12.5 | 13.5 / 14 |
| 46 | 306.7 | 29.33 | 29.17 | 295 | 11.5 | 12.5 | 13.5 / 14 |
| 46.5 | 310.0 | 29.67 | 29.50 | 295 | 12 | 13 | 14 / 14.5 |
| 47 | 313.3 | 30.00 | 29.83 | 300 | 12.5 | 13.5 | 14.5 / 15 |
| 47.5 | 316.7 | 30.33 | 30.17 | 305 | 13 | 14 | 15 / 15.5 |
| 48 | 320.0 | 30.67 | 30.50 | 305 | 13 | 14 | 15 / 15.5 |
All 39 rows span from toddler size EU 16 through junior crossover EU 35, including the ISO children's growth last (1.08 × foot + 6 mm). UK and US sizing resets from 13.5 back to Adult 1 around EU 32.5.
| EU | ISO child last (mm) | ISO foot (cm) | Mondopoint | UK Child | US Child (ISO) |
|---|---|---|---|---|---|
| 16 | 106.8 | 9.33 | 95 | 1 | 1.5 |
| 16.5 | 110.4 | 9.67 | 95 | 1.5 | 2 |
| 17 | 114.0 | 10.00 | 100 | 2 | 2.5 |
| 17.5 | 117.6 | 10.33 | 105 | 2 | 2.5 |
| 18 | 121.2 | 10.67 | 105 | 2.5 | 3 |
| 18.5 | 124.8 | 11.00 | 110 | 3 | 3.5 |
| 19 | 128.4 | 11.33 | 115 | 3.5 | 4 |
| 19.5 | 132.0 | 11.67 | 115 | 4 | 4.5 |
| 20 | 135.6 | 12.00 | 120 | 4 | 4.5 |
| 20.5 | 139.2 | 12.33 | 125 | 4.5 | 5 |
| 21 | 142.8 | 12.67 | 125 | 5 | 5.5 |
| 21.5 | 146.4 | 13.00 | 130 | 5.5 | 6 |
| 22 | 150.0 | 13.33 | 135 | 5.5 | 6 |
| 22.5 | 153.6 | 13.67 | 135 | 6 | 6.5 |
| 23 | 157.2 | 14.00 | 140 | 6.5 | 7 |
| 23.5 | 160.8 | 14.33 | 145 | 7 | 7.5 |
| 24 | 164.4 | 14.67 | 145 | 7.5 | 8 |
| 24.5 | 168.0 | 15.00 | 150 | 7.5 | 8 |
| 25 | 171.6 | 15.33 | 155 | 8 | 8.5 |
| 25.5 | 175.2 | 15.67 | 155 | 8.5 | 9 |
| 26 | 178.8 | 16.00 | 160 | 9 | 9.5 |
| 26.5 | 182.4 | 16.33 | 165 | 9.5 | 10 |
| 27 | 186.0 | 16.67 | 165 | 9.5 | 10 |
| 27.5 | 189.6 | 17.00 | 170 | 10 | 10.5 |
| 28 | 193.2 | 17.33 | 175 | 10.5 | 11 |
| 28.5 | 196.8 | 17.67 | 175 | 11 | 11.5 |
| 29 | 200.4 | 18.00 | 180 | 11.5 | 12 |
| 29.5 | 204.0 | 18.33 | 185 | 11.5 | 12 |
| 30 | 207.6 | 18.67 | 185 | 12 | 12.5 |
| 30.5 | 211.2 | 19.00 | 190 | 12.5 | 13 |
| 31 | 214.8 | 19.33 | 195 | 13 | 13.5 |
| 31.5 | 218.4 | 19.67 | 195 | 13 | 13.5 |
| 32 | 222.0 | 20.00 | 200 | 13.5 | 1 (adult) |
| 32.5 | 225.6 | 20.33 | 205 | 1 (adult) | 2 (adult) |
| 33 | 229.2 | 20.67 | 205 | 1.5 (adult) | 2.5 (adult) |
| 33.5 | 232.8 | 21.00 | 210 | 2 (adult) | 3 (adult) |
| 34 | 236.4 | 21.33 | 215 | 2 (adult) | 3 (adult) |
| 34.5 | 240.0 | 21.67 | 215 | 2.5 (adult) | 3.5 (adult) |
| 35 | 243.6 | 22.00 | 220 | 3 (adult) | 4 (adult) |
A 3 or 4 mm measuring error shifts the result by half a shoe size. Follow these four steps on a hard floor, never on carpet:
An EU 42 shoe last measures 280 mm (28 cm). Recommended bare-foot length is 26.5 cm for everyday closed-toe shoes (15 mm allowance), 26.7 cm on the ISO/TS 19407 baseline (Mondopoint 265), 27 cm in snug dress shoes, and 26–26.2 cm in running shoes or winter boots.
EU, UK, and US sizes label the shoe last rather than the foot, and makers build between 10 and 20 mm of toe room plus different toe shapes. A running shoe with 18 mm allowance pushes a 265 mm foot up to EU 42.5, while a 10 mm dress last fits the same foot at EU 41.5.
Mondopoint (ISO 9407) is the only system that states bare-foot length directly in millimetres, stepping in 5 mm increments (for example 265 for a 26.5 cm foot). Specialist, military, and ski boots often list width in millimetres alongside length, such as 265/98.
Adding 33 to a UK size breaks across the range because one UK barleycorn is 8.47 mm while one EU Paris point is 6.67 mm. The actual difference shifts from 32 at UK 3 (EU 35) to 33 at UK 7 (EU 40) and 34.5 at UK 12 (EU 46.5).
Size up for closed-toe, athletic, or hiking footwear, since feet lengthen slightly during exercise and heat. If tightness comes from a wide forefoot rather than toe length, look for a wider fitting width (such as E/EE or a Mondopoint width code) instead of going up two lengths.
Every table row and converter calculation comes directly from published international footwear sizing formulas, without hidden offsets or arbitrary retail rounding.