I guess so vs Perhaps

When to use each in English, with meaning, register, and examples.

I guess so

InformalTop 3,000 (common)

Perhaps

Top 1,000 (very common)A2adverb
Most formal: PerhapsMost common: Perhaps
 I guess soPerhaps
Pronunciation🇬🇧 //aɪ ɡɛs səʊ//🇺🇸 //aɪ ɡɛs soʊ//🇬🇧 /["/pəˈhæps//præps/"]/🇺🇸 /["/pərˈhæps/"]/
MeaningIt's a way of saying you agree to something uncertain.maybe; it might be true
ExampleAre you coming to the party tonight? I guess so.‘Are you going to come?’ ‘Perhaps. I'll see how I feel.’
RegisterInformalNeutral
How commonTop 3,000 (common)Top 1,000 (very common)
CEFR level-A2
Part of speechadverb
CollocationsI guess so, I guess not, I guess that's trueperhaps we should, perhaps it is, perhaps he thought
AntonymsI don't think so, I doubt it, I disagree, Definitely notdefinitely, certainly
Common mistakesUsing in formal settings where more certainty is needed., Saying it too emphatically, making it sound definite., Omitting other responses that could clarify uncertainty.'Perhaps' can't be used as a noun., Confused with 'perchance', which is more archaic., Using 'perhaps' in very direct or commanding statements.
Usage notesUse this when you're not fully certain but lean towards an agreement. Avoid in formal conversations.Use 'perhaps' in formal writing or speech. It's less common in casual conversations, where 'maybe' is preferred. Avoid using it when being certain.

See it in real clips

I guess so
Perhaps

Frequently asked questions: I guess so vs Perhaps

What's the difference between I guess so and Perhaps?

I guess so: It's a way of saying you agree to something uncertain. Perhaps: maybe; it might be true

Which is more formal: I guess so and Perhaps?

Perhaps is the most formal of these.

Which is more common: I guess so and Perhaps?

Perhaps is the most common in everyday English.

Can you show an example of each?

I guess so: Are you coming to the party tonight? I guess so. Perhaps: ‘Are you going to come?’ ‘Perhaps. I'll see how I feel.’

Can I use I guess so and Perhaps interchangeably?

Not always. I guess so and Perhaps are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.

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