How to calculate the toner coverage 5%

The average consumption of a laser printer toner, both in black and white and in colour, is measured according to ISO/IEC, which refers to a page with the same characteristics as the image.

The text and images reproduced correspond to 5% of the total area of the page.

If your page is denser than the exposed one, the life of the cartridge will be shorter than the pages declared by the manufacturer. And vice versa.