About Stats Calculator Online
Stats Calculator Online is a free collection of statistics and math calculators with transparent formulas, step-by-step output, similar calculator widgets, learning tidbits, and APA-style reporting. Every results page includes free exports: citation / write-up, LaTeX, CSV, Word/Docs, and Print/PDF. Everything runs in your browser—fast and private.
Our full name is always Stats Calculator Online (statscalculatoronline.com) so search keywords stay clear and unbroken.
Tidbits from Stats Calculator Online
Everyday math
Percent change ≠ percent of
Percent of is part÷whole. Percent change uses the starting value in the denominator—and +50% then −50% does not return to start.
Percentage calculators →Quick tip
Sample vs population SD
Use n−1 (sample) when your data are a subset of a larger group; use n when you truly have the whole population.
Open SD calculator →Tidbit
A p-value is not the probability H₀ is true
It is the probability of data at least as extreme as yours if H₀ were true. Pair it with an effect size and confidence interval.
P-value calculator →