Binomial Probability Calculator
Math ToolsChance of exactly, at most or at least k successes
FreePrivateInstant
Similar tools you may like
History
All history →Binomial Probability Calculator — at a glance
Find the chance of getting k successes in n tries.
10 trials
p = 0.5
k = 6
Calculate
P(X = k)
How to use it — step by step
Number of trials, success probability and k.
1
Enter your values
Fill in the fields. Default numbers are shown so you can see how it works.
2
Press Calculate
The answer appears at once as large result cards.
3
Copy or share
Copy the result, or share a link that opens with your numbers filled in.
Pro tips
Small things that make the result better.
✦Trials must be independent with the same chance each time.
✦Enter the probability as a decimal, like 0.25.
✦Coin flips and quality checks fit well.
Quick facts
Freeno signup
Privateruns in your browser
Instantresult in a second
No limituse it as often as you like
Frequently Asked Questions
What is a binomial experiment?+
A fixed number of independent tries, each either a success or a failure with the same chance.
How large can n be?+
Up to 10,000 trials.
Is my data safe?+
Yes. Everything runs inside your own browser. Your text, files and images are never uploaded to any server.
Is this tool really free?+
Yes — completely free, no signup, no watermark and no usage limit.
More Free Tools
Guides you might like
All guides →Pascal’s Triangle GeneratorPascal's triangle: patterns, coin flips and the numbers behind combinationsConfidence Interval Calculator (Mean)Confidence intervals explained: what 95% really means and how sample size shrinks itZ-Score CalculatorZ-score explained: compare anything on one scale and spot outliersPercent Error CalculatorPercent error: how far off is your measurement, and how it differs from percent change