About ztable.co

ztable.co is a free reference tool for anyone working with the standard normal distribution: an interactive z table, a z-score calculator, p-value tools, and printable downloads (PDF, CSV and PNG) that teachers and students can use freely in classes and coursework.

How the values are computed

Every probability on this site is computed directly from the standard normal cumulative distribution function (using the mathematical error function), not copied from other tables — which is why values are consistent to five decimal places across the table, the calculators and the downloads.

Languages

The tool is available in English, Spanish, Portuguese, Indonesian, Hindi, Turkish and Vietnamese — statistics homework is international.

Contact

Corrections, suggestions or questions: contact@ztable.co