The amount of ink you get from a cartridge can be measured by either page yield or cartridge capacity.
Page yield is the approximate number of pages that can be printed with a particular cartridge. For the majority of our printer cartridges, you’ll find the page yield listed in the cartridge specs table on the product page. This is a standardized value provided by the printer manufacturer that is based on the amount of ink inside the cartridge and ISO page yield testing (find out more on how page yield is calculated here).
In some instances, the printer manufacturer may not provide the page yield and instead provide the cartridge ink capacity in milliliters (ml). When page yield is not available, we include the ink capacity in our specs table. This should be seen as a supplemental value as some printers can use the ink differently than others. If ink capacity is the only value available to measure the ink volume in your cartridge, we recommend printing with the cartridges to determine the approximate page yield for your printer use. Page yield and ink capacity are just two factors that help you determine how many printed pages you can expect to get out of a specific cartridge. Other factors like what you print, how often you print and whether you are printing in black, color, or a combination of both, also affect the number of printed pages, which can vary greatly from user to user.
A specs table example of the HP 63XL high yield black printer cartridge page yield
A specs table example of the Canon CLI-281XL high yield magenta cartridge capacity (measured in milliliters)