Guides
Correct Sitting Posture at a Desk
You have been told to sit up straight since you were about six, it has never lasted more than twenty minutes, and you would like to know what you are actually aiming for.
By Michael W. · Published · Specs verified
Picked on published fit specifications, not on hands-on testing. How we pick.
The short answer
There is no single correct posture, and that is the most useful thing to know. What you are aiming for is a supported neutral position you can hold without effort, and then changing out of it regularly. A posture you have to concentrate to maintain is the wrong one.
This page sits under Guides. If you want the fit numbers before the shortlist, start with the seat height guide and the seat depth guide.
"Sit up straight" is bad advice
Rigid upright sitting is muscular work. You can hold it for a few minutes, then your postural muscles fatigue and you slump - usually into something worse than where you started. Cycling between rigid and slumped all day is more tiring than either.
The useful goal is a supported neutral position: one the chair holds you in, so you are not spending effort on it. That means a slight recline against a backrest that carries some of your weight, rather than a vertical spine held by willpower.
What supported neutral looks like
| Body part | Where it should be | The common error |
|---|---|---|
| Head | Ears roughly over shoulders, chin level | Pushed forward, chasing a screen that is too low |
| Shoulders | Relaxed and down, not shrugged | Lifted to meet armrests set too high |
| Upper back | In contact with the backrest | Unsupported above the shoulder blades on a short backrest |
| Lower back | Natural inward curve, supported | Flattened, because the pelvis has rolled backward |
| Pelvis | Neutral, weight through the sit bones | Rolled back onto the sacrum and tailbone |
| Hips | Level with or slightly above the knees | Below the knees, closing the hip angle |
| Knees | Roughly 90 to 110 degrees, gap behind them | Pressed against the front edge of a too-deep seat |
| Feet | Flat on the floor or a footrest | Dangling, or tucked under the chair |
| Elbows | At your sides, forearms roughly horizontal | Reaching forward for a keyboard too far away |
Every one of those is achievable with the adjustments in how to adjust your office chair, and none of them requires concentration once the chair is set.
The one that matters most: the pelvis
If you only fix one thing, fix this. When the pelvis rolls backward - which happens whenever you slump, or when your feet do not reach the floor, or when the seat is too deep and you slide forward - the lumbar spine flattens out of its natural inward curve and load transfers onto soft tissue that was not built to hold it for hours.
Almost every other posture error follows from this one. The head goes forward because the upper back rounded, and the upper back rounded because the pelvis rolled back. Fix the bottom and the top largely fixes itself.
Three things keep the pelvis neutral: feet supported, seat not too deep, and lumbar support at your curve. That is the whole of it.
The 100-110 degree question
You will see a range of recommended backrest angles, and the sources genuinely differ. The OSHA computer workstation guidance describes a backrest supporting the natural curve of the lower back without prescribing a single angle. Cornell's ergonomics group argues for a more reclined working posture than the conventional upright one.
What they agree on: bolt upright is not the target, and a backrest that carries some of your weight is better than one you sit away from. Somewhere slightly past vertical is a sensible place to start, and the exact number matters less than actually leaning into it.
The positions that reliably cause trouble
- Perching on the front edge with no back contact. Usually a symptom of a seat that is too deep. All the load, none of the support.
- Sitting on a wallet, phone or one folded leg. Tips the pelvis to one side and loads one side of the lumbar spine harder than the other.
- Crossed legs for long stretches. Rotates the pelvis and the lumbar spine with it.
- Leaning on one elbow. Side-bends the spine. Usually caused by armrests at different heights or a mouse too far to one side.
- Laptop on the lap on a sofa. The worst combination available, and the one most people spend their evenings in after optimizing their desk.
- Feet tucked under the chair. Not a posture, a symptom: the chair is too high and your feet are looking for something to rest on.
No posture survives eight hours
This is the part the checklists leave out. Even a perfect supported neutral held motionless all day will make your back ache, because the problem is static loading rather than the specific position.
Practical: use two postures. Recline for reading, calls and thinking; sit forward for typing. Switch with the task rather than with a timer, because task-based switching actually happens. Stand for calls.
What the published guidance says about frequency, and where the confident numbers you see quoted come from, is in how long should you sit in an office chair.
Posture is downstream of fit
You cannot sit well in a chair that does not fit you. If your feet do not reach the floor, your pelvis will roll backward no matter how much you concentrate. If the seat is longer than your thigh, you will perch or slump, and both are worse than either.
Get your two numbers first - seat height and seat depth - and then worry about posture. In that order, because the second one is largely automatic once the first is right.
When a chair will not fix this
Posture advice is for ordinary desk discomfort. It is not the right response to pain with any of these features:
- Pain that runs below the knee, or numbness and tingling in the foot
- Weakness in a leg or foot, or a foot that catches when you walk
- Pain that wakes you at night, or that is worse lying down than sitting
- Sudden onset after a fall, a lift, or an impact
- Any change in bladder or bowel control, or numbness around the groin - this one is urgent
- Pain with unexplained weight loss, fever, or a history of cancer
See the NIH NINDS back pain overview and a clinician rather than another posture checklist.
We are not doctors, physical therapists or certified ergonomists, and nothing here is medical advice. If you are in real pain, see someone who is qualified to look at it.
Questions people actually ask
What is the correct sitting posture at a desk?
A supported neutral you can hold without effort: pelvis neutral, lumbar curve supported, feet flat, shoulders relaxed, head over shoulders, and the backrest slightly past vertical carrying some of your weight. Then change out of it regularly.
Should I sit up straight?
Not rigidly upright. That is muscular work, it fatigues within minutes, and you end up slumped. A slight recline against a supportive backrest is easier to hold and puts less load through the spine.
Is it bad to cross your legs at a desk?
For long stretches, yes - it rotates the pelvis and the lumbar spine with it, loading one side more than the other. Crossing your legs briefly is not a problem; holding it for an hour is.
How do I stop slouching?
Usually not by trying harder. Slouching is normally the result of a chair that is too high, a seat that is too deep, or no lumbar support - all of which make slouching the path of least resistance. Fix those and it largely stops on its own.
Sources
- OSHA Computer Workstations eTool - Chairs
- Cornell University Ergonomics Web (CUErgo)
- Allsteel, Ergonomics and Design: A Reference Guide - Table 1 and Table 2, 5th-95th percentile adult body dimensions (BIFMA Ergonomics Guidelines, 2002), hosted by Oregon State University EHS
- NIH National Institute of Neurological Disorders and Stroke - Back Pain