How the cost per page calculator works
The whole formula
Cost per page = cartridge price ÷ pages it prints. Everything else is commentary — and the commentary is where printers hide: ISO yields assume 5% coverage (a bare memo), real documents run 8–15%, so honest math discounts yield 20%. A $22 cartridge yielding 300 honest pages prints at 7.3¢/page; the box implied 4¢.
The razor-and-blades model
Printers sell at or below manufacturing cost because the ink is the product: margins run 50%+ on cartridges and negative on hardware. The industry term is "free razor, expensive blades" — and the defense is arithmetic before purchase: cost per page, not price on the shelf. A $60 printer at 8¢/page loses to a $200 printer at 1.5¢/page before box two of ink.
The color multiplier
Color pages cost 3–5× mono: four cartridges participate instead of one. The color-share input matters because households printing 80% black pages should compare mono cost primarily — while photo-heavy households live in the color line. Blended cost is what the year actually costs; the split tells you where it went.