The are several prime sieves, all of which are designed to find all of the prime numbers up to some finite limit \(n\). The sieve of Eratosthenes is an ancient algorithm, and is the one used in this applet. Begin by arranging the numbers 1 through \(n\) in a grid, with at least as many columns as rows. Starting with 2, cross off all multiples of each number \(i\) in the top row except for the \(i\) itself. The numbers that remain are all prime.

Click on any box to remove the multiples of a number. The size of the grid will be determined by the size of your browser window, up to 27 numbers per row.

This applet was created using JavaScript and the Raphael library. If you are unable to see the applet, make sure you have JavaScript enabled in your browser. This applet may not be supported by older browsers.