Par time

Each level in Doom has an associated par time. After completing a level, the par time is displayed on the intermission screen next to the the time that the player took to complete the level. This allows the player to gauge their skill by comparing their time.

The par times are encoded into the Doom executable in the file. John Romero generated the par times by completing each level as fast as possible and adding 30 seconds.

Par times
The following are the par times from the Doom source code:

Doom

 * E1M1:30s
 * E1M2:1m15s
 * E1M3:2m
 * E1M4:1m30s
 * E1M5:2m45s
 * E1M6:3m
 * E1M7:3m
 * E1M8:30s
 * E1M9:2m45s
 * E2M1:1m30s
 * E2M2:1m30s
 * E2M3:1m30s
 * E2M4:2m
 * E2M5:1m30s
 * E2M6:6m
 * E2M7:4m
 * E2M8:30s
 * E2M9:2m50s
 * E3M1:1m30s
 * E3M2:45s
 * E3M3:1m30s
 * E3M4:2m30s
 * E3M5:1m30s
 * E3M6:1m30s
 * E3M7:2m45s
 * E3M8:30s
 * E3M9:2m15s

Doom II

 * MAP01: 30s
 * MAP02: 1m30s
 * MAP03: 2m
 * MAP04: 2m
 * MAP05: 1m30s
 * MAP06: 2m30s
 * MAP07: 2m
 * MAP08: 2m
 * MAP09: 4m30s
 * MAP10: 1m30s
 * MAP11: 3m30s
 * MAP12: 2m30s
 * MAP13: 2m30s
 * MAP14: 2m30s
 * MAP15: 3m30s
 * MAP16: 2m30s
 * MAP17: 7m
 * MAP18: 2m30s
 * MAP19: 3m30s
 * MAP20: 2m30s
 * MAP21: 4m
 * MAP22: 2m30s
 * MAP23: 3m
 * MAP24: 2m30s
 * MAP25: 2m30s
 * MAP26: 5m
 * MAP27: 5m30s
 * MAP28: 7m
 * MAP29: 5m
 * MAP30: 3m
 * MAP31: 2m
 * MAP32: 30s