Home Office Ergonomics: Desk, Screen, Chair and Light, in Numbers

Desk height: 28 to 30 inches, but measure your own elbow

Sit in the chair you actually use, feet flat on the floor, shoulders down, upper arms hanging beside your ribs. Bend your elbows to about 90 degrees and measure from the floor to the underside of your forearm. That number is your desk height. For most adults it lands between 28 and 30 inches, which is why fixed desks are built there — but mass-market desks cluster at 29 to 30, a height that suits somebody around five foot ten and nobody shorter. At five foot four the right surface is closer to 26 inches, and eight hours of typing at 30 inches means eight hours of shrugged shoulders. There are two honest fixes for a desk that is too tall. Raise the chair until your forearms are level and add a footrest, so your feet stay supported and your knees stay near 90 degrees. Or fit a keyboard tray, which drops the typing surface an inch or two below the desktop and leaves the desk itself for paper. Either way, keep your wrists straight rather than bent up over the front edge, and leave the flip-out feet on the back of your keyboard folded down — they tilt the keyboard toward you and push your wrists into extension, which is the opposite of what they look like they are doing. If you handwrite for much of the day, a slightly higher surface really is more comfortable. That is the one case where the elbow rule bends.

• Most adults: 28–30 in at a fixed desk
• Measure floor to underside of forearm, elbows at 90 degrees
• Desk too tall: raise the chair and add a footrest
• Keyboard feet folded down, wrists straight

Monitor distance and height, and why desk depth beats desk width

Put the top of the screen at or just below eye level, so your gaze drops slightly rather than climbing. Ten to 20 degrees below horizontal is the comfortable band, and it matters for more than the neck: a screen set high holds your eyelids open wider and dries your eyes. Distance is 20 to 30 inches, roughly your arm at full stretch. A 24-inch monitor is comfortable at 24 to 26 inches, a 27-inch at 28 to 32, and a 32-inch or an ultrawide wants 30 to 36, which most desks simply cannot deliver. This is why depth, not width, is the desk dimension that decides your setup. On a 24-inch-deep desk the monitor stand foot eats eight or nine inches, so even shoved to the back edge the panel sits about 20 inches from your face, and anything larger than a 24-inch screen is then too close to take in without moving your head. A 30-inch-deep desk solves it outright. A monitor arm is the cheaper fix: it removes the stand foot and lets the panel cantilever past the back edge, buying back six to eight inches without buying furniture. A laptop on its own can never be right, because the screen and the keyboard are bolted at the same height — one of the two is always in the wrong place. A riser plus an external keyboard resolves both for very little money. If you wear progressive lenses, drop the screen another inch or two so you are not tipping your head back to find the reading zone.

Adjust the chair in this order: height, depth, lumbar, arms

Order matters, because each adjustment changes the one after it. Height first: feet flat, thighs roughly parallel to the floor, and two to three inches of clearance between the front edge of the seat and the back of your knee. If the desk is fixed and too tall, set the chair to the desk and use a footrest rather than letting your feet dangle. Depth second: with your back against the backrest you want two to three fingers of gap behind the knee. A seat that is too deep forces you to perch forward, which abandons the backrest entirely — the most expensive part of the chair, unused. Lumbar third: the fullest point of the support belongs in the inward curve of your lower back, usually six to nine inches above the seat pan, roughly at belt level. If the chair has no adjustment there, a rolled towel in the right place beats a cushion in the wrong one. Armrests last: raise them until they just meet your elbows with your shoulders relaxed, which puts them level with the desk surface at 28 to 30 inches. Armrests higher than the desk stop you pulling the chair in, and that one fault causes more forward-leaning than any other. Then set the recline tension so the chair follows you when you lean back, and actually use it — a reclined 100 to 110 degrees loads the spine less than a rigid upright 90.

• Seat height: thighs level, 2–3 in behind the knee
• Seat depth: 2–3 fingers between seat edge and calf
• Lumbar: fullest point 6–9 in above the seat pan
• Armrests: level with the desk, 28–30 in from the floor
• Recline to 100–110 degrees rather than sitting bolt upright

A sit-stand desk is only as good as the top of its range

Standing elbow height, measured the same way as seated, is what a standing desk has to reach. For most adults that is 38 to 46 inches; at six foot two it is closer to 47 or 48. Manufacturers advertise a maximum, and it is worth checking whether that figure includes a desktop — a frame quoted at 47 inches with a one-inch top gives you a 48-inch desk, while the same number quoted with the top already fitted does not. Two inches short and you stand with your shoulders raised, which is more tiring than sitting badly. The bottom of the range catches shorter users the other way: plenty of frames stop at 25 to 28 inches, and if your seated elbow height is 25 you have bought a desk you cannot sit at. Two things people forget when they buy one. The monitor has to travel with the desk, so clamp the arm to the desk rather than to a wall or a shelf, or you gain nothing on the standing side. And a hard floor punishes standing, which makes an anti-fatigue mat more valuable than most of the features on the spec sheet. On timing, the useful target is variety rather than standing hours: 30 to 45 minutes upright in each hour suits most people, and the benefit comes from the change of position. Standing rigidly for four hours just swaps one set of complaints for another.

Window position, and why backlighting ruins a video call

A camera exposes for the brightest thing it can see. Sit with a window behind you and it exposes for the window, which turns your face into a silhouette, and no amount of software correction recovers detail that was never captured. Put the window in front of you instead — ideally about 45 degrees off the camera axis and three to six feet away, so the light wraps across your face rather than flattening it. A sheer curtain turns direct sun into something usable. For the desk itself the calculus is different: facing straight into a window puts a bright field in your sightline all day, and sitting with your back to one puts a reflection of that window on your screen. The arrangement that solves both is a desk turned so the window sits roughly perpendicular to your line of sight, with the monitor on the far side from the glass. Where no wall allows it, a blind plus a small lamp behind the monitor at about face height will carry a call adequately. Avoid lighting yourself from a ceiling fitting directly overhead. It drops shadow into your eye sockets and under your nose, which reads as exhausted regardless of how you actually feel, and it is the single most common reason people look worse on camera at home than at the office.

• Window in front, about 45 degrees off the camera axis, 3–6 ft away
• Never with a window directly behind you
• Desk turned so the window is perpendicular to your sightline
• Fill light behind the monitor at face height, not overhead

Task light does the work; the overhead does not

A ceiling fixture on its own is behind you when you sit at a desk, so your own body throws the shadow onto whatever you are reading, and the fitting reflects in a glossy screen. Aim for roughly 300 lux of general light in the room and 500 at the desk surface for reading and writing, 750 if the work is fine and detailed. The way to get there is a dedicated task lamp rather than a brighter bulb overhead. Put it on the side opposite your writing hand — left side if you are right-handed, so your hand does not shadow the page — with the head 15 to 20 inches above the desk and angled so the bulb itself never appears in your sightline. Then match the screen to the room. A bright monitor in a dim room is the fastest route to eye strain there is, because your pupils re-adjust every time you look away from it; the screen should read about as bright as the wall behind it. Around 3500 to 4000 K keeps colour crisp during working hours, with something warmer in the evening if the office doubles as a bedroom. Add the 20-20-20 habit on top: every 20 minutes, look at something 20 feet away for 20 seconds. It costs nothing and rests the focusing muscle the rest of this is trying to protect.

Cable management is an ergonomics problem, not a tidiness one

Cables decide where things sit. A three-foot laptop charger puts the laptop wherever the outlet is, which is never where your eyes want it. A monitor cable that runs six inches short pulls the screen off-centre, and you will spend a year turning your neck rather than buying a longer lead. On a sit-stand desk, taut cabling is worse than untidy cabling, because the desk stops travelling at whatever height the shortest cable allows — usually a couple of inches below where you needed it. Measure the travel of the desk, often 20 to 25 inches, and add at least 30 inches of slack to every cable before you bundle anything, then run the bundle in a chain or spine that folds rather than one that stretches. Under the desk, protect the knee space: 24 inches wide is the minimum and 30 is comfortable, and it should stay clear to a depth of 20 to 24 inches at knee level. A tower, a bin or a coiled power strip in that zone makes you sit at an angle, and a spine twisted for eight hours a day undoes every other adjustment on this page. Mount the power strip under the desktop instead of leaving it on the floor, and keep cables out from under the castors — a chair that will not roll gets dragged, and that is a shoulder complaint waiting to happen.

Common questions

Worked out for a real footprint

The same rules, applied to a specific room size in inches.