| POS | BIB | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|---|
| 1 | 667 | Steven GARDINER | 
                                         
                                        BAH
                                     | 
                                    43.89 Q NR | 0.186 | 
| 2 | 1071 | Nathon ALLEN | 
                                         
                                        JAM
                                     | 
                                    44.19 Q PB | 0.161 | 
| 3 | 1413 | Fred KERLEY | 
                                         
                                        USA
                                     | 
                                    44.51 q | 0.137 | 
| 4 | 688 | Kévin BORLÉE | 
                                         
                                        BEL
                                     | 
                                    45.10 | 0.146 | 
| 5 | 1422 | Wilbert LONDON | 
                                         
                                        USA
                                     | 
                                    45.12 | 0.181 | 
| 6 | 871 | Óscar HUSILLOS | 
                                         
                                        ESP
                                     | 
                                    45.16 PB | 0.163 | 
| 7 | 1249 | Rafał Omelko | 
                                         
                                        POL
                                     | 
                                    45.37 | 0.201 | 
| 8 | 952 | Dwayne COWAN | 
                                         
                                        GBR
                                     | 
                                    45.96 | 0.144 | 
| POS | BIB | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|---|
| 1 | 1282 | Wayde VAN NIEKERK | 
                                         
                                        RSA
                                     | 
                                    44.22 Q | 0.168 | 
| 2 | 712 | Baboloki THEBE | 
                                         
                                        BOT
                                     | 
                                    44.33 Q | 0.178 | 
| 3 | 1266 | Abdalelah Haroun | 
                                         
                                        QAT
                                     | 
                                    44.64 q SB | 0.179 | 
| 4 | 961 | Matthew HUDSON-SMITH | 
                                         
                                        GBR
                                     | 
                                    44.74 SB | 0.142 | 
| 5 | 1325 | Lalonde Gordon | 
                                         
                                        TTO
                                     | 
                                    45.20 | 0.151 | 
| 6 | 1055 | Brian GREGAN | 
                                         
                                        IRL
                                     | 
                                    45.42 | 0.188 | 
| 7 | 1426 | LaShawn Merritt | 
                                         
                                        USA
                                     | 
                                    45.52 | 0.195 | 
| 8 | 1143 | Boniface Ontuga MWERESA | 
                                         
                                        KEN
                                     | 
                                    45.93 | 0.234 | 
| POS | BIB | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|---|
| 1 | 708 | Isaac MAKWALA | 
                                         
                                        BOT
                                     | 
                                    44.30 Q | 0.248 | 
| 2 | 1084 | Demish GAYE | 
                                         
                                        JAM
                                     | 
                                    44.55 Q PB | 0.157 | 
| 3 | 1431 | Gil Roberts | 
                                         
                                        USA
                                     | 
                                    44.84 | 0.170 | 
| 4 | 766 | Jamal Walton | 
                                         
                                        CAY
                                     | 
                                    45.16 | 0.153 | 
| 5 | 689 | Jonathan BORLÉE | 
                                         
                                        BEL
                                     | 
                                    45.23 | 0.203 | 
| 6 | 833 | Pavel MASLÁK | 
                                         
                                        CZE
                                     | 
                                    45.24 | 0.146 | 
| 7 | 1324 | Machel CEDENIO | 
                                         
                                        TTO
                                     | 
                                    45.91 | 0.221 | 
| 8 | 1065 | Davide RE | 
                                         
                                        ITA
                                     | 
                                    45.95 | 0.186 |