In 15 Seconds
- Use when you are 80-90% sure about a fact.
- Stronger than 'I think' but softer than 'I'm positive.'
- Perfect for professional and social settings alike.
Meaning
Use this when you are about 80% to 90% sure about something. You aren't totally positive, but you would be very surprised if you were wrong.
Key Examples
3 of 6Checking a schedule with a colleague
I'm fairly certain the meeting starts at three o'clock.
I am reasonably sure the meeting is at 3:00.
Trying to remember if you did a chore
I'm fairly certain I turned off the oven before we left.
I'm pretty sure I turned off the stove.
In a job interview
I'm fairly certain my skills align perfectly with this role.
I am quite confident I am a good fit.
Cultural Background
Brits use 'fairly certain' as a form of 'litotes' or understatement. It can sometimes mean they are 100% sure but don't want to sound arrogant. In US business culture, 'fairly certain' is used to manage expectations. It signals that while the speaker is confident, they are not legally guaranteeing the outcome. Japanese learners often over-use 'I think' because it feels safer. Switching to 'fairly certain' helps them sound more authoritative in English-speaking environments. German speakers might find 'fairly certain' confusing because their equivalent 'ziemlich sicher' is very direct. They should be careful not to interpret 'fairly' as 'weak' in English.
The 90% Rule
Use 'fairly certain' when you would bet $100 on it, but not your whole house.
Avoid with 'Very'
Don't say 'very fairly certain.' It's redundant and sounds strange to native ears.
In 15 Seconds
- Use when you are 80-90% sure about a fact.
- Stronger than 'I think' but softer than 'I'm positive.'
- Perfect for professional and social settings alike.
What It Means
Fairly certain is your middle-ground expression for confidence. It means you have a strong feeling that something is true. You have some evidence or a good memory of it. However, you are leaving a tiny bit of room for error. It is much stronger than saying I think. It is slightly less intense than saying I am positive.
How To Use It
You can use it to answer questions or state facts. It usually comes after the verb to be. For example, I am fairly certain. You can also follow it with that to explain a situation. I'm fairly certain that I locked the door. It sounds natural and confident without being arrogant. Use it when you want to sound reliable but honest.
When To Use It
Use it at work when a boss asks for a status update. Use it with friends when trying to remember a movie title. It is perfect for those moments when you don't want to bet your life savings. It works great in restaurants when ordering. I'm fairly certain I'll have the pasta. It shows you have made up your mind. It is a very safe, polite way to share information.
When NOT To Use It
Do not use it if you are 100% sure. If you saw the thief, don't say you are fairly certain. In that case, say I am positive. Also, avoid it if you are totally guessing. If you have no idea, fairly certain sounds like a lie. Don't use it in high-stakes legal situations either. It implies a small shadow of a doubt.
Cultural Background
English speakers, especially in the UK and North America, love understatement. We often avoid saying I am 100% sure to avoid looking foolish. Using fairly acts as a social safety net. It makes you seem thoughtful and careful with your words. It is a hallmark of polite, professional conversation. It suggests you are a person who checks their facts.
Common Variations
Pretty sure(More casual and very common)Reasonably confident(More formal or academic)Fairly confident(Great for job interviews)Almost certain(Slightly higher level of certainty)Quite sure(Very common in British English)
Usage Notes
This phrase is a 'neutral' register, meaning it works anywhere from a coffee shop to a business meeting. Be careful with your tone; if you say it slowly, it can sound like you are actually doubting yourself.
The 90% Rule
Use 'fairly certain' when you would bet $100 on it, but not your whole house.
Avoid with 'Very'
Don't say 'very fairly certain.' It's redundant and sounds strange to native ears.
The British 'Fairly'
Be careful: if a British person says they are 'fairly certain,' they might be 100% sure but just being polite.
Examples
6I'm fairly certain the meeting starts at three o'clock.
I am reasonably sure the meeting is at 3:00.
Shows professional confidence while allowing for a slight mistake.
I'm fairly certain I turned off the oven before we left.
I'm pretty sure I turned off the stove.
Expresses a strong memory of an action.
I'm fairly certain my skills align perfectly with this role.
I am quite confident I am a good fit.
Sounds confident without being overly aggressive.
I'm fairly certain the bar is on the next corner.
I'm pretty sure the bar is right here.
Short, clear communication for navigation.
I'm fairly certain my cat is actually the one in charge here.
I'm pretty sure my cat runs this house.
Uses a serious phrase for a funny observation.
I'm fairly certain that everything is going to work out for us.
I feel quite sure things will be okay.
Provides comfort and reassurance.
Test Yourself
Fill in the missing words to express 90% certainty.
I'm _______ _______ that I left my umbrella at the restaurant.
'Fairly certain' is the most natural collocation for this level of confidence.
Which sentence is the most polite way to correct someone in a meeting?
Someone says the project is due Friday, but you think it's Thursday.
Using 'fairly certain' hedges the statement and makes it more polite.
Complete the dialogue.
A: Is John coming to the party? B: I'm ________ ________ he is, but he hasn't texted me back yet.
The second half of the sentence ('he hasn't texted back') explains why the speaker isn't 100% sure.
Match the phrase to the level of certainty.
Match 'Fairly Certain' with its percentage.
'Fairly certain' represents a high degree of confidence, usually around 80-90%.
🎉 Score: /4
Visual Learning Aids
Practice Bank
4 exercisesI'm _______ _______ that I left my umbrella at the restaurant.
'Fairly certain' is the most natural collocation for this level of confidence.
Someone says the project is due Friday, but you think it's Thursday.
Using 'fairly certain' hedges the statement and makes it more polite.
A: Is John coming to the party? B: I'm ________ ________ he is, but he hasn't texted me back yet.
The second half of the sentence ('he hasn't texted back') explains why the speaker isn't 100% sure.
Match 'Fairly Certain' with its percentage.
'Fairly certain' represents a high degree of confidence, usually around 80-90%.
🎉 Score: /4
Frequently Asked Questions
10 questionsYes, 'fairly certain' is better for emails and work, while 'pretty sure' is for friends.
Yes, you can say 'certain of [noun]' or 'certain that [clause].'
Usually around 80% to 95%.
It is 'fairly.' 'Fairy' is a magical creature!
Yes: 'I was fairly certain I saw him yesterday.'
No, it sounds honest and realistic, which many employers value.
The opposite would be 'completely unsure' or 'totally uncertain.'
Yes: 'She seems fairly certain about her choice.'
In American English, yes. In British English, 'quite' can be stronger.
In the US, it's often a 'glottal stop'—you don't really say the 't.'
Related Phrases
pretty sure
similarInformal version of fairly certain.
reasonably certain
similarCertain based on logic.
dead certain
contrast100% sure.
not entirely certain
contrastHaving some doubts.
