First 2 in each heat (Q) and the next 2 fastest (q)

First 2 of each heat (Q) plus 2 fastest times (q) qualify to Final

POS Rank Heat BIB ATHLETE COUNTRY RESULTS ms*
1 1 3 1427 Sydney MCLAUGHLIN-LEVRONE USAUSA 48.29 Q WL
2 2 3 851 Amber ANNING GBRGBR 49.38 Q SB
3 3 3 1035 Nickisha PRYCE JAMJAM 49.46 q SB
4 1 2 613 Salwa Eid NASER BRNBRN 49.47 Q
5 1 1 1198 Natalia BUKOWIECKA POLPOL 49.67 Q SB
6 2 2 711 Roxana GÓMEZ CUBCUB 49.78 Q SB
7 2 1 741 Marileidy PAULINO DOMDOM 49.82 Q
8 3 1 1176 Henriette JÆGER NORNOR 49.87 q
9 4 3 658 Martina WEIL CHICHI 49.88
10 3 2 1451 Isabella WHITTAKER USAUSA 50.20
11 4 2 1144 Lieke KLAVER NEDNED 50.25
12 5 2 1045 Stacey Ann WILLIAMS JAMJAM 50.39 .381
13 4 1 566 Sada WILLIAMS BARBAR 50.39 SB .389
14 5 1 1383 Aaliyah BUTLER USAUSA 50.63
15 6 1 935 Wadeline VENLOGH HAIHAI 50.67
16 5 3 746 Bassant HEMIDA EGYEGY 50.69
17 6 2 559 Printassia JOHNSON BAHBAH 50.81
18 6 3 1249 Andrea MIKLÓS ROUROU 50.90 SB
19 7 3 774 Paula SEVILLA ESPESP 50.97
20 8 3 958 Sharlene MAWDSLEY IRLIRL 51.22
21 7 2 1096 Mercy Adongo OKETCH KENKEN 51.36
22 7 1 1034 Dejanea OAKLEY JAMJAM 51.42
23 8 1 864 Yemi Mary JOHN GBRGBR 51.51
24 8 2 875 Victoria OHURUOGU GBRGBR 51.65
Legend

ms - Milliseconds - shown when two or more competitors finish with the same time down to hundredths of a second