The industry-standard assumption that a typical page has ink or toner on 5% of its surface — roughly a page of ordinary text. Toner yields and click charges are quoted against this benchmark.
When a manufacturer says a toner cartridge yields 20,000 pages, that figure assumes 5% coverage. It is a laboratory benchmark, not a promise about your documents.
Five per cent is about what a standard letter or invoice uses. If your pages carry photographs, full-width headers, block colour or dense graphics, real coverage can easily be three or four times that — and your toner will run out proportionally faster.
This matters most when comparing quotes. Two suppliers quoting the same click charge are quoting against the same 5% assumption, so the comparison is fair. But if you print heavy graphics, expect your actual consumable usage to run ahead of the headline yield.