NMAKE returns an exit code to the operating system or the calling program. A value of 0 indicates execution of NMAKE with no errors. Warnings return exit code 0.
| Code | Meaning |
| 0 | No error |
| 1 | Incomplete build (issued only when /K is used) |
| 2 | Program error, possibly due to one of the following: |
| A syntax error in the makefile | |
| An error or exit code from a command | |
| An interruption by the user | |
| 4 | System error—out of memory |
| 255 | Target is not up to date (issued only when /Q is used) |