I want to inquire about the difference in meaning between these two sentences:

The code must work perfectly.
The code should work perfectly. 

For instance how the usage of "must" and "should" in the previous sentences will change the meaning?

  • Did you look up the definitions of must and should? What differences did you find? – stangdon Mar 27 '18 at 19:40

English modals have a lot of shades of meanings, but to keep it simple, for this specific situation:

Should X expresses unconfirmed belief that X happened or will happen. It is synonymous with is expected to X:

The code should work perfectly (but we won't know for sure until we try it.)

Must X expresses that something cannot happen unless X happened or definitely will happen. It is synonymous with is required to X or has to X.

The code must work perfectly (or our job isn't complete, etc.)

Should X can be used as a polite or gentler must X.

| improve this answer | |

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.