Statistics

Critical Value Calculator

Calculate critical values for Z (standard normal), t, chi-square, and F distributions from alpha (α) or confidence level. Supports one-tailed and two-tailed setups with clear steps.

Z critical (z*) t critical (t*) χ² critical F critical One / Two-tailed
This calculator uses numerical approximations for distribution functions. For most typical stats use-cases (common α and df ranges), results match standard tables closely.

Critical Value Finder

Choose a distribution, enter alpha or confidence level, select tail type, then compute critical cutoff(s).

Confidence level converts to α using α = 1 − CL.
Two-tailed splits α into α/2 on each side (where applicable).
If using α: enter a decimal like 0.05 (or switch to percent below).
Examples: 0.05 = 5%, or enter 5 with Percent.
Used for t and chi-square tabs.
Used for F (df1 = df, df2 = df2).
Chi-square is not symmetric. Two-tailed setups return two cutoffs (lower and upper) using α/2 in each tail.
F is right-skewed and used mainly with a right-tail cutoff. For two-tailed, this tool returns both cutoffs (left and right), but many standard ANOVA workflows focus on the upper critical value.