Page Yield

The Page Yield, for example the figure such as '540 pages', that you often see printed on the packaging containing your ink or toner cartridge, should give you a rough idea of how many pages you can print before you'll need to replace your printer cartridge. In fact, the standards organisation ISO has even come up with a specification of what constitutes a typical page so that different ink manufacturers can test their cartridges and come up with a consistent 'like-for-like' figure. However, you should be mindful of the following...

5% Coverage

The standard used to calculate the number of pages is based on a 5% coverage of the printed page. The ISO standard actually specifies what the test pages should look like. However, if your page is completely covered in ink, as you would expect in a photograph, then you can assume 100% coverage instead. All of a sudden the ink cartridge page yield can now be divided by 20. That means if you take the example of 540 pages, all of a sudden you're down to 27 pages before replacement.

15% Coverage

For colour cartridges some manufacturers base the number of pages on a 15% coverage of the printed page, which will in theory provide a more generous estimate of the yield. To know who uses this estimate, all we can say is 'read the small print' - sorry.

Tri-Colour

If you have all your colours contained in one tri-colour cartridge  - cyan, magenta and yellow - and you use up one colour before all the others you may experience the disappointment of knowing that you could still have lots of ink left, but not be able to use it. You may wish to buy a printer with separate ink cartridges next time around.