Minecraft wiki entry for Item_(entity), associated text: The player may be thought of as having an "item pickup" box that surrounds their hitbox. This pickup box extends 1 additional block to the horizontal sides, and 0.5 additional blocks up and down. Any item whose hitbox intersects with the pickup box can be picked up. The pickup box is inclusive on the horizontal sides (distance less than or equal to 1 will count), and exclusive on the vertical sides (distance less than 0.5 will count, but not equal). When the player's hitbox size changes, such as when crouching‌[Java Edition only] or sleeping, the pickup box size changes with it.