Correct sitting posture at a computer (what 'good' actually looks like)

Search "correct sitting posture" and you get a diagram of a person sitting at perfect right angles, looking like they were assembled from a manual. It's not wrong, exactly. It's just not how spines work.

Here's the honest version — the one we'd give a friend. There is no single correct posture you're meant to hold all day. The healthiest posture is the next one: your body is built to move, and any position held long enough becomes the bad one. But there is a neutral baseline worth knowing cold, because it's the position you return to — the one that costs the least to hold, and the one every "sit up straight" instinct should be aiming at.

This is that baseline, head to feet. Learn it once and you stop guessing.

What "good posture" actually means

Forget rigid and military. A good seated posture has three properties, and not one of them is "straight":

1. Neutral — your joints sit near the middle of their range, not jammed at an end. Your spine keeps its natural curves: a small inward curve in the lower back, a gentle outward one in the upper back. Not forced flat, not arched.
2. Low-effort — you can hold it without bracing. If "good posture" is exhausting, it isn't good posture; it's a plank.
3. Easy to leave and return to — you can shift, lean, stand, and come back. Movement is a feature, not a failure.

If a position has those three, it's good. The checklist below is just the fastest way to find it.

The head-to-feet checklist

Work from the bottom up. The spine follows the pelvis, and the pelvis follows the feet — so fixing the base does most of the work for you.

Feet

Flat on the floor, taking real weight. If they dangle, lower the chair or add a footrest. Dangling feet roll the pelvis backward and the whole stack collapses from the ground up.

Knees

Roughly 90°, thighs about parallel to the floor or sloping very slightly down. Leave a 2–3 finger gap between the front edge of the seat and the back of your knees — too deep and you'll slide forward all day.

Hips & pelvis — the one that matters most

Sit on your sit bones, the two bony points at the base of your pelvis, not rolled back onto your tailbone. This is the master switch. When the pelvis tips backward, the lumbar curve flattens, the upper back rounds, the shoulders roll forward, and the head juts to keep your eyes level. The entire slouch is, mechanically, a pelvis problem first. We go deep on why in how to stop slouching. (Tipped the other way — lower back over-arched, belly forward? That's anterior pelvic tilt.)

Lower back

Keep its small natural inward curve. A chair with adjustable lumbar set at belt-line height does this for you; a rolled-up towel does it for free. The goal is support of the existing curve, not a forced arch.

Recline angle

Counterintuitive, but well-supported: a slight recline of 100–110° rather than a rigid vertical 90° actually loads the lumbar discs less. Let the backrest carry some of your weight instead of hovering off it.

Ribcage & shoulders

Ribs stacked over pelvis — not flared up, not collapsed down. Shoulders back and down, relaxed, not shrugged toward your ears. If your shoulders creep up while you type, your armrests or your desk are too high.

Head & neck

Ears stacked over shoulders, eyes level. This is the payoff of everything beneath it: get the base right and the head lands neutral on its own, no effort required. It matters because the load adds up fast — for every inch your head drifts forward, the effective weight on your cervical spine climbs steeply (a 15° tilt is ~27 lb; a 45° phone-reading tilt is ~49 lb). The fix isn't a stronger neck; it's not letting the head travel in the first place. That forward drift is exactly what tech neck is.

The screen — the hidden lever

None of the above survives a monitor that's too low. Top of the screen at eye level, about an arm's length away. A low screen drags your eyes down, then your head, then your whole spine. It's the highest-ROI fix there is, and it's free — the full hierarchy is in the ergonomic desk setup checklist.

Why the "correct" posture still won't stick

Here's the part the diagrams never mention: you can know this checklist perfectly and still be slumped twenty minutes later. That's not a willpower failure — it's two forces working against you.

The first is drift. You sit down neutral, and without a single conscious decision you're 2 cm forward by the time you surface from a hard task. The second is static fatigue: the small postural muscles that hold you upright quietly inhibit when held still, even at low load. By hour three your spine is hanging on its ligaments.

So the two countermeasures aren't "try harder." They're:

1. Move before you'd think to. Static loading climbs sharply after about 30 minutes in any one position — even a textbook-perfect one. Stand, walk, or just reset every half hour. The damage is in the stillness, not only the angle.
2. Externalize the check. You can't reliably watch your own posture while you're concentrating — the part of your brain that would notice you're slumping is busy doing your job. Hand the watching to something else: a timer, or a webcam coach that only pings you when you've actually drifted below your own calibrated baseline. That's the entire reason StopSlouching exists. More on why memory-based fixes fail in how to stop slouching.

The mistakes that quietly undo it

Even with the base dialed in, a handful of habits drag you back out of neutral. The five we see most in webcam data: craning toward the screen to read small text, rounding the shoulders to reach a too-narrow keyboard, the one-leg-up tuck that twists the pelvis, the slow afternoon slide, and the head-dip to a phone lying face-up on the desk. Each is fixable in under a minute once you know to look for it.

If your neck or back already hurts

This checklist prevents; it doesn't treat. If you've already got the tight upper traps and aching neck of forward-head posture, pair good sitting with the five stretches that target those exact muscles. If it's your lower back, the desk-side back-pain fixes are the place to start. Sitting well is what stops you re-loading those muscles between sessions, so the stretches actually get a chance to work.

The minimum effective dose

If you remember nothing else from this: sit on your sit bones, raise your screen to eye level, and move every 30 minutes. The first finds neutral, the second keeps your head from traveling forward, and the third stops any position — good or bad — from setting like concrete.

Not sure which part you're getting wrong? The 60-second posture quiz scores your habits and hands you your top three fixes. Or just watch yourself for a full work hour — the number of times you leave neutral in a single work hour is almost always a surprise.