ztable.io

by MarkVD · ztable.io · Education

Established publisherManifest V3 Free

View in Chrome Web Store Data as of 16 Oct 2026

Z-table lookup: Find the percentage of values below a given z-score in a standard normal distribution.

Users

+1 in 30 days

Rating

0.0 / 5

unchanged in 30 days

Ratings

0 in 30 days

Store rank

#127K

#105K among extensions

Version

1.0.0

updated 26 Oct 2023

Users

monthly, 3 years

Latest, 16 Oct 2026: 33 usersMove the mouse over the chart for any month

Ratings count

monthly, 3 years

Latest, 16 Oct 2026: 0 ratingsMove the mouse over the chart for any month

The Chrome Web Store rounds user counts down to the leading digit, so the user line moves in steps. The ratings count is exact and is the better signal of real adoption.

About ztable.io

A tool to quickly calculate probabilities in a normal distribution from a z-score table. You can either use the slider or enter a z-score value in the input field to find, among other things, the percentage of values below or above this value in a standard normal distribution. You can also: - Compute probabilities between two z-scores. - Calculate a z-score by entering a test value, a mean value and a standard deviation. - Read and understand how to use a positive and negative z-table.