A 48x24-inch desk gives you ample space for your keyboard, mouse, and a 27-inch...

https://arthursuniquethoughts.publishlane.com/posts/how-much-room-do-i-need-to-roll-my-chair-back-safely

A 48x24-inch desk gives you ample space for your keyboard, mouse, and a 27-inch monitor without feeling cramped. Pair that with at least 36 inches of clearance behind your chair to move comfortably during long sessions