Both mean possibly, and in most sentences you can swap them freely. Perhaps is more formal and is the usual choice in writing; maybe is more conversational and commoner in speech. Maybe also has a separate life as a noun ("a definite maybe") that perhaps does not.
The core difference
They are near-perfect synonyms as adverbs. The gap between them is tone: perhaps belongs to more formal registers, maybe to everyday speech. "Perhaps we should reconsider" and "Maybe we should reconsider" carry the same probability and different clothing.
Where they differ in practice
- Position. Both sit comfortably at the start of a sentence, but perhaps moves around more easily inside one: "This is, perhaps, the better option" reads naturally in a way "This is, maybe, the better option" does not.
- Politeness. Perhaps is the standard hedge in a request or a disagreement — "Perhaps we could look at this again" softens without sounding casual.
- Word class. Maybe can be a noun: "The answer was a maybe." Perhaps cannot.
The trap: maybe and may be
The real error in this area is not choosing between the two words but writing maybe when you need may be. May be is a verb phrase: "She may be late." Maybe is an adverb: "Maybe she is late." Test by substituting perhaps — if the sentence still works, you want the one-word maybe; if it collapses, you need may be.
Which to write
In formal or professional writing, perhaps is the safer default. In dialogue, marketing copy or anything conversational, maybe will sound less stiff. Neither is wrong in the other's territory; they just sound like it.
Frequently asked questions
Is perhaps more formal than maybe?
Yes. They mean the same, but perhaps is the usual choice in formal and written English, while maybe is more conversational.
What is the difference between maybe and may be?
Maybe is one word and means perhaps: "Maybe she is late." May be is two words and is a verb phrase: "She may be late." If perhaps fits in the slot, use the one-word maybe.
Can maybe be a noun?
Yes — "the answer was a maybe" is standard. Perhaps cannot be used this way.