Ja 4
Fit verdict, size conversion guide, and millimeter measurements.
This shoe runs approximately 1.7mm shorter than standard sizing. If you are between sizes or prefer a relaxed fit, go a half size up.
Aggregated feedback from verified shoe owners
| EU | US (M) | UK | Foot Length | Cavity Length |
|---|---|---|---|---|
| 35.5 | 3.5 | 3 | 21.6 cm | 230.29 mm |
| 36 | 4 | 3.5 | 22.0 cm | 234.29 mm |
| 36.5 | 4.5 | 4 | 22.4 cm | 238.29 mm |
| 37.5 | 5 | 4.5 | 22.9 cm | 243.29 mm |
| 38 | 5.5 | 5 | 23.3 cm | 247.29 mm |
| 38.5 | 6 | 5.5 | 23.7 cm | 251.29 mm |
| 39 | 6.5 | 6 | 24.1 cm | 255.29 mm |
| 40 | 7 | 6 | 24.5 cm | 259.29 mm |
| 40.5 | 7.5 | 6.5 | 25.0 cm | 264.29 mm |
| 41 | 8 | 7 | 25.4 cm | 268.29 mm |
| 42 | 8.5 | 7.5 | 25.8 cm | 272.29 mm |
| 42.5 | 9 | 8 | 26.2 cm | 276.29 mm |
| 43 | 9.5 | 8.5 | 26.7 cm | 281.29 mm |
| 44 | 10 | 9 | 27.1 cm | 285.29 mm |
| 44.5 | 10.5 | 9.5 | 27.5 cm | 289.29 mm |
| 45 | 11 | 10 | 27.9 cm | 293.29 mm |
| 45.5 | 11.5 | 10.5 | 28.3 cm | 297.29 mm |
| 46 | 12 | 11 | 28.8 cm | 302.29 mm |
| 47 | 12.5 | 11.5 | 29.2 cm | 306.29 mm |
| 47.5 | 13 | 12 | 29.6 cm | 310.29 mm |
| 48 | 13.5 | 12.5 | 30.0 cm | 314.29 mm |
| 48.5 | 14 | 13 | 30.5 cm | 319.29 mm |
| 49 | 14.5 | 13.5 | 30.9 cm | 323.29 mm |
| 49.5 | 15 | 14 | 31.3 cm | 327.29 mm |
| 50 | 15.5 | 14.5 | 31.7 cm | 331.29 mm |
| 50.5 | 16 | 15 | 32.2 cm | 336.29 mm |
| 51 | 16.5 | 15.5 | 32.6 cm | 340.29 mm |
| 51.5 | 17 | 16 | 33.0 cm | 344.29 mm |
| 52 | 17.5 | 16.5 | 33.4 cm | 348.29 mm |
| 52.5 | 18 | 17 | 33.9 cm | 353.29 mm |
| 53 | 18.5 | 17.5 | 34.3 cm | 357.29 mm |
| 53.5 | 19 | 18 | 34.7 cm | 361.29 mm |
| 54 | 19.5 | 18.5 | 35.1 cm | 365.29 mm |
| 54.5 | 20 | 19 | 35.5 cm | 369.29 mm |
| 55 | 20.5 | 19.5 | 36.0 cm | 374.29 mm |
| 55.5 | 21 | 20 | 36.4 cm | 378.29 mm |
| 56 | 21.5 | 20.5 | 36.8 cm | 382.29 mm |
| 56.5 | 22 | 21 | 37.2 cm | 386.29 mm |
Does the Nike Ja 4 run big or small?
It tends to run slightly small. We recommend going a half size up for the best fit. This shoe runs approximately 1.7mm shorter than standard sizing. If you are between sizes or prefer a relaxed fit, go a half size up.
How does Shoe Fit determine shoe sizing?
Shoe Fit calculates the real-world interior shoe cavity in millimeters combined with real owner feedback, rather than relying on arbitrary brand charts.
Already own a shoe that fits well? Shoe Fit cross-references its internal cavity against the Nike Ja 4 to give you your personalized size.
Help other shoppers find their perfect fit by adding your rating.
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