| POS | Rank | Heat | BIB | ATHLETE | COUNTRY | RESULTS | ms* |
|---|---|---|---|---|---|---|---|
| 1 | 1 | 2 | 379 | Brian FAUST |
USA |
45.89 Q | .881 |
| 2 | 2 | 2 | 396 | Jacory PATTERSON |
USA |
45.89 Q | .886 |
| 3 | 1 | 1 | 371 | Christopher BAILEY |
USA |
45.91 Q | |
| 4 | 3 | 2 | 124 | Matheus LIMA |
BRA |
46.22 Q | |
| 5 | 2 | 1 | 226 | Attila MOLNÁR |
HUN |
46.32 Q | |
| 6 | 3 | 1 | 138 | Christopher MORALES-WILLIAMS |
CAN |
46.62 Q | |
| 7 | 4 | 2 | 221 | Patrik Simon ENYINGI |
HUN |
46.93 | |
| 8 | 4 | 1 | 345 | Boško KIJANOVIĆ |
SRB |
47.20 | |
| 9 | 5 | 1 | 260 | Rusheen MCDONALD |
JAM |
47.22 | |
| 10 | 5 | 2 | 110 | Cooper SHERMAN |
AUS |
47.67 | |
| 11 | 6 | 2 | 354 | Lionel SPITZ |
SUI |
47.72 | |
| 12 | 6 | 1 | 276 | Fuga SATO |
JPN |
48.31 |
ms - Milliseconds - shown when two or more competitors finish with the same time down to hundredths of a second