Sang is the simple past tense; sung is the past participle, which only appears after a helper verb such as have, has, had, was or were. She sang three songs at the wedding. She has sung at every family wedding since 2019.
The core difference
Sing is an irregular verb with three forms: sing, sang, sung. Sang does the work on its own — it is the whole verb of the sentence. Sung cannot stand alone; it needs a helper (an auxiliary verb) propping it up.
How to use each
Use sang when you are simply reporting something that happened:
- He sang along to the radio the entire way home.
- The crowd sang before the whistle went.
- I sang in a choir for six years.
Use sung after a form of have (perfect tenses) or a form of be (passive):
- She has sung that aria in four countries.
- By the time we arrived, the anthem had been sung.
- That hymn is sung at nearly every service.
The test you can run
Look immediately to the left of the word. If there is a helper verb there — have, has, had, was, were, is, are, been, being — the answer is sung. If there is no helper, the answer is sang.
It works the same way for the other verbs in this family, which is why remembering one pattern covers several: ring/rang/rung, drink/drank/drunk, swim/swam/swum, begin/began/begun. If "I have drank" sounds wrong to you, then "I have sang" is wrong for exactly the same reason.
Where people slip
The mistake almost always runs in one direction: sang used where sung belongs, as in "I've sang that song a hundred times." This is common in speech across many varieties of English, and it is one of those forms that people notice in writing. If you are writing anything checked by an editor, an examiner or a hiring manager, use have sung.
The reverse error is rarer but does turn up in ambitious prose: "He sung the last verse alone." Some older poetry and hymn texts use sung as a simple past, so it can feel literary — but in modern standard English it reads as an error, not a flourish.
One more thing worth noting: sung can also work as an adjective in front of a noun, and that is perfectly correct. A sung Mass is one that is sung rather than spoken. Here it is still a participle, just doing a describing job.
