Find the minimum landing depth for your stair. Codes require at least the stair width, and never less than 36 inches in the direction of travel.
A landing must be at least as deep, in the direction of travel, as the stair is wide, and never less than 36 inches under the IRC. Where a door swings onto the landing, the depth must also clear the swing so no one is pushed toward the steps.
At least as deep as the stair is wide, and never less than 36 inches in the direction of travel under the IRC.
Yes. If a door swings over the landing, the landing must be deep enough that the swing does not push a person toward the stairs.
Not every one, but a landing is required where a flight exceeds the maximum rise between landings, or to change direction in L- and U-shaped stairs.