doomath Calculator
Confidence Interval Calculator
Estimate a two-sided confidence interval from a sample mean, standard deviation, sample size and confidence level.
InputsChange a value to recalculate instantly
ResultUpdates as you type
FORMULA & STEPSConfidence Interval Calculator — Mathematical Derivation & Steps
λ DooMathWork with this calculation
Local · deterministic · optionalQuick mathNatural-language-style shortcuts for deterministic arithmetic.
Calculator guide
How to use the Confidence Interval Calculator
Estimate a two-sided confidence interval from a sample mean, standard deviation, sample size and confidence level.
01Set inputsChoose values, units and assumptions.
02Apply the modelCI = x̄ ± z·(σ/√n)
03Read the resultCheck the output against the assumptions before using it.
What this calculator does
Estimate a two-sided confidence interval from a sample mean, standard deviation, sample size and confidence level.
Formula & method
CI = x̄ ± z·(σ/√n)
Assumptions & notes
Review the inputs, units and assumptions before using the result for a real decision.