A windmill is a place where you can grind grain into flour. To use the mill, a player must place their grain into the hopper on the top floor and operate the hopper controls. The flour can be collected on the ground floor[UK]1st floor[US], by using a pot on the flour bin, or left-clicking the bin. Making flour does not grant players any Cooking experience. The flour bin can hold a maximum of 30 flour before it is full.
Windmills are marked on the map with a yellow icon ().
The mill in Zanaris, with a cow running on the wheel.
- The Zanaris mill is not powered by wind - instead, it is powered by a cow.
- All but one flour bins across Gielinor are linked. Therefore, if a player leaves flour in one location, it can be retrieved later at any other windmill except the one on Harmony Island.
- Sweetcorn can be put in the hopper, to obtain a pot of cornflour for Recipe for Disaster. However, the mill on Harmony Island will not work for this, stating that the mill is "not built well enough to be used for anything but flour".
- The fact that the flour bin can hold 30 flour is likely a vestige of Runescape Classic, when players' inventories could hold 30 items instead of the current 28.
- Mary & Gordon's farm in the Kebos Lowlands also features a windmill, but while its sails do connect to a set of gears on the 1st floor[UK]2nd floor[US], the upright shaft it powers does not extend downstairs, and consequently it cannot be used to produce flour, nor is it marked with an icon on the map.
- The special grain from the Tombs of Amascut grain sack can't be added to any windmill's hopper.