Most sitting advice boils down to a single idea: keep your body in a handful of comfortable right angles. It's often called the 90-90-90 rule, and it's a useful starting point whether you're setting up a home office for the first time or adjusting a desk you've used for years.
The three angles
The rule refers to your hips, knees and elbows, each aiming for roughly a 90-degree bend:
- Hips at about 90°, with your thighs roughly parallel to the floor
- Knees at about 90°, feet flat on the floor or a footrest
- Elbows at about 90°, wrists level with your keyboard
None of these need to be exact. Think of them as a target, not a rule you'll be graded on.
Getting there with what you already have
If your chair sits too low, a seat cushion can lift you into a better hip angle without buying new furniture. If your feet don't reach the floor once you're at the right height, a footrest closes that gap. And if your wrists bend up or down at the keyboard, it's usually the desk height — or the chair — that needs adjusting, not your typing habits.
Small corrections like these add up. You won't feel the difference in an afternoon, but you will by the end of the week.
