Confidence Interval
Calculate the confidence interval for a sample mean given sample size, mean, standard deviation and confidence level.
Confidence interval for a mean
CI = mean ยฑ zยทฯ/โn. We use the normal z-multiplier; for small samples (n < 30) prefer Student's t.
Frequently Asked Questions
Is the Confidence Interval free to use?
Yes, the Confidence Interval is 100% free to use. There are no subscriptions, no sign-ups, and no hidden fees.
Is my data safe when using the Confidence Interval?
Absolutely. All calculations performed by the Confidence Interval happen locally in your web browser. We do not store, track, or transmit your inputs or results to any server.
How accurate is the Confidence Interval?
Our Confidence Interval uses industry-standard formulas and methodology. You can view the exact formula and calculation logic used in the methodology section above to verify the math yourself.
Can I use the Confidence Interval on my mobile phone?
Yes! The Confidence Interval is fully responsive and works seamlessly on all devices including smartphones, tablets, and desktop computers.