Sank vs. Sunk
“Sank” is the usual simple past of “sink,” while “sunk” is the past participle. Cambridge also records “sunk” as an alternative simple-past form in US English, so the page distinguishes the core tense pattern from that regional variation.
Use “sank” for the usual simple past (“The boat sank”) and “sunk” after an auxiliary (“The boat has sunk”). US English also permits “sunk” as a simple-past variant.
Key details
Choose the right form
| Meaning / situation | Form / construction | Decision |
|---|---|---|
| usual simple past of “sink” | sank | Use “sank” as the usual simple-past form. |
| past participle after have/has/had | sunk | Use “sunk” in perfect constructions. |
| simple past in US English | sunk can also occur | Cambridge records “sunk” as an alternative US simple-past form, so this is a regional variant rather than an absolute error. |
Quick tests
Meaning / construction test
Does the form follow have/has/had and therefore require the past participle?
If yes: Use “sunk.”
If no: Use “sank” as the usual simple past, while recognizing documented US simple-past “sunk.”
Caveat: The core pattern is “sank” for the usual simple past and “sunk” for the participle, but US English also permits “sunk” as a simple-past variant.
Examples
The boat sank during the storm.
“Sank” is the usual simple-past form.
The boat has sunk near the harbor.
“Has” requires the past participle “sunk.”
In US English, “The boat sunk” can occur as a documented simple-past variant.
Cambridge records “sunk” as an alternative US simple-past form.
Further guidance
Core difference
“Sank” is the usual simple-past form; “sunk” is the past participle used with auxiliaries such as has, have, or had.
Regional Boundary
Cambridge also records “sunk” as an alternative simple-past form in US English, so “sank” versus “sunk” is not an absolute two-box rule in every variety.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- Sink — Cambridge Dictionary (opens in a new tab)Cambridge University Press · Direct verb-form evidence: Cambridge gives sank (and in US use also sunk) as past tense and sunk as the past participle of sink.