English UsageGrammar guide
May vs. Might
May and might both express possibility and often overlap. Might can sound more tentative in many contexts, but a rigid certainty percentage is unreliable; tense, reported speech and speaker stance can also affect the choice.
Both may and might can express possibility. Might is often more tentative, but do not treat them as a fixed probability scale in every context.
Key details
Certainty Boundarynative-speaker judgments do not support one universal probability ladder
May Rolepossibility and, in some contexts, permission
Might Rolepossibility often presented more tentatively, plus backshift/hypothetical uses
Further guidance
Grammar Boundary
Might also appears in backshifted and hypothetical structures where simple substitution with may can change the construction.
Possibility Boundary
May and might overlap heavily for possibility; context and speaker stance matter.
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.
- Could, may and might — Cambridge Grammar (opens in a new tab)Cambridge Dictionary · May and might for possibility, including uncertainty about fixed certainty rankings