Measure First: Reading Your Own Body Before You Buy Anything

Measuring the body before buying anything

This chapter walks through taking four measurements — seated elbow height, seated eye height, standing elbow height, standing eye height — using a tape measure, a relaxed shoulder posture, and shoes matched to how you actually work. It explains why a shrugged shoulder or dangling feet quietly falsifies the number you record, and why footwear thickness changes the answer. It follows a running example, Mara, working at a kitchen table, through recording her own numbers alongside her current desk, chair, and screen heights, and shows the gap between them: her table sits four inches above her elbow height, her laptop screen sits twelve inches below her eye height. The chapter untangles frame height, finished desktop height, and typing height as three separate numbers people mistake for one, using Ergotron's ergonomic equation as a reference for how elbow angle should drive the setup rather than the furniture. It also covers how a chair's seat depth and footrest use affect what the elbow number even means, drawing on a chair fit guide and an elbow support explainer. Mara then makes one free adjustment — a seat cushion and a stack of books as a footrest — and tests it against reach, visibility, support, and stability, discovering that raising a laptop lid to fix screen height wrecks typing height, since the two are one hinged object.

What a display's own numbers tell you

Before any mount or stand gets chosen, the chapter lists what to know about a screen itself: its bare panel weight without the factory base, its dimensions and chassis depth, its screw-hole spacing on the back, and whether those holes sit in a recess. It then shows how to calculate a stand's full height range and compare it against eye height, using OSHA's monitor placement guidance, a monitor height guide, and a sit-stand monitor height guide. It flags where the standard "top of screen at eye level" rule breaks down — large or stacked monitors, bottom-heavy work like terminals, and progressive lens wearers — pulling on ViewSonic's screen positioning advice, and closes by tying desk height back into the same arithmetic using a desk height calculator.

The first tool in a computer workstation build is a tape measure. Not a shopping page, not a review video, not a sale alert. A tape measure, a pen, and something to write on.

Here is why. Almost every piece of equipment on a desk is sold by a number. A desk is sold by how low and how high it goes. A monitor arm is sold by how much weight it holds and how far it lifts. A keyboard is sold by how many keys it has and how it splits apart. Those numbers are all answers. The trouble is that most people buy them without ever asking the question. They do not know how high their own elbows sit when they are relaxed. So they buy a desk, hope, and then spend the next year quietly shrugging their shoulders for eight hours a day.

This show builds a workstation out of what you already own and the space you already have, in an order that makes sense for your body, your tasks and your budget. Cheap and free changes first, then the surface, then the screen, then what your hands touch. This chapter is the part that has to come first, because everything after it is decided by four numbers and one honest look at the furniture you already have. By the end you will know how to take those numbers, where to write them down, and how to make one free change and test whether it actually helped.

One thing before we start. This is a gear and setup show. I can explain mechanics and fit, and I can tell you what the measurements mean. I cannot tell you that any product will prevent or cure pain. If something hurts and keeps hurting, that belongs with a qualified person who can assess you, not with a more expensive chair. An adjustment is an adjustment, not a treatment.

Now let me introduce the example we will carry through this build, so the numbers have a person attached to them.

Her name is Mara. She works on a laptop at a kitchen table. She types for long stretches, she is on video calls several times a day, and she does some fiddly image work where a few pixels matter. Nothing about her setup is unusual and nothing about it is on purpose. The table was there, the laptop was there, and the arrangement is whatever happened.

Every figure I give for Mara is an example figure. It is there so you can watch the reasoning work on real numbers. It is not your number. Your numbers will be different, and that is the whole point of measuring.

Let us take the four body measurements. There are only four, and each one has a landmark and a posture that has to be right before the number means anything.

Start seated, because that is where most of the work happens. Sit all the way back in the chair so your lower back is supported. Adjust the seat height until your feet rest completely flat on the floor, your thighs are roughly horizontal, and your knees are about level with your hips. Check the front edge of the seat. There should be a gap of two to four finger-widths between that edge and the back of your knee. If the seat is pressing into the back of your knee, slide back or use a shallower position, because that pressure squeezes the blood flow in your leg.

If the chair will not go low enough to get your feet flat, or if you have had to raise it to reach a table that does not move, put your feet on something solid before you measure anything. A stack of books, a sturdy box, a proper footrest. Dangling feet are not a small problem. Your feet are the base of everything above them. When they hang, your pelvis rolls and your whole upper body settles into a different shape, and the measurement you take from that shape describes a posture you would never choose to work in.

Footwear matters too, and in a specific way. For seated measurements, measure in whatever you actually have on your feet at the desk. Barefoot if you work barefoot. Shoes if you wear them. For standing, always wear the shoes you would really stand and work in. A sole is often half an inch thick or more, and that half inch lifts your elbows and your eyes off the floor by the same amount. Measure in slippers, buy for sneakers, and you have bought the wrong height.

Now the posture for the arms, and this is the one people get wrong. Let your upper arms hang straight down at your sides. Shoulders relaxed and dropped. Not lifted, not pushed forward. Then bend your elbows to somewhere around ninety to a hundred degrees, so your forearms are parallel to the floor or angled very slightly downward. Wrists straight, in line with the forearms, not bent up and not bent down.

Hold that, and measure straight up from the floor — or from the top surface of your footrest, if you are using one — to the underside of the bony point of your elbow. That is your seated typing height. It is the height at which the keys your fingers rest on should sit, and the height your mouse should sit at too.

Why the fuss about relaxed shoulders? Because a shrug is worth an inch or two, easily, and it does not feel like anything while you are doing it. If you lift your shoulders while you measure, you record a number higher than your real one. Then you set your keyboard to that number, and to reach it you shrug all day. The measurement has quietly built the problem into the furniture. It helps to breathe out, let your arms go completely heavy for a moment, and only then bring the forearms up.

Second number, same seated posture. Look straight ahead, level, with your neck at rest and not tilted. Measure from the floor, or the footrest, up to the center of your pupils. That is your seated eye height. It is a ceiling for the top of your screen, not a target for the middle of it.

Third and fourth numbers, standing. Shoes on. Feet about hip-width apart, knees unlocked rather than jammed straight. Shoulders dropped, upper arms hanging, elbows at that same ninety to a hundred degrees. Measure floor to the underside of the elbow point: that is your standing typing height. Then look level and measure floor to pupils: standing eye height.

Two practical notes on taking these. A rigid tape measure held against a flat wall is much easier to read than a floppy one held in mid-air, and a second person makes it far easier still. Measure each one twice. If the two readings disagree by more than about half an inch, your posture is drifting between attempts, so reset and go again.

Here are Mara's four, as example figures. Seated typing height, twenty-six inches. Seated eye height, forty-five inches. Standing typing height, in the shoes she wears at home, forty-one inches. Standing eye height, sixty inches.

Those four numbers describe her. Now we measure the room, because the room is what she has to work with.

Write down the height of the current typing surface, measured from the floor to the top of it. Write down the seat height and whether the feet reach the floor. Write down where the screen sits: how high the top of the picture is off the floor, and how far it is from your eyes when you are working normally. Write down how deep the surface is from front edge to wall, and how wide. Write down where the electrical outlets are and how far away. And get under there with the tape: how much clear space is there between the floor and the underside of the surface, and is anything in the way — a drawer, an apron rail, a table leg where your knees want to be.

Mara's kitchen table is thirty inches from the floor to the top. Her chair seat is eighteen inches. Her feet do reach the floor. The laptop sits flat on the table, and the top of its screen is about thirty-three inches off the floor. The table is twenty-four inches deep, which is shallow, and the nearest outlet is behind her on the wall.

Compare her body to her furniture and the problem is right there in the numbers. Her seated typing height is twenty-six inches. Her typing surface is thirty. That is four inches too high, so to reach the keys she either lifts her shoulders or bends her wrists up, and she has been doing some of both. Meanwhile her seated eye height is forty-five inches and the top of her screen is at thirty-three, twelve inches lower. So her neck drops forward to read it. Wrists up, neck down, all day.

There is a distinction hiding inside that four-inch gap, and it will matter every time you look at a desk. There are three different heights involved and people talk about them as if they were one. There is the frame height, which is what the metal legs reach on their own. There is the finished desktop height, which is the frame plus the thickness of the top you put on it. And there is the typing height, which is the finished desktop plus the thickness of your keyboard, measured up to the keys your fingers actually rest on.

Work it forward and it looks like this. Say a frame goes down to twenty-eight inches. Put a one-inch top on it, and the surface is at twenty-nine. Set a keyboard on that whose home row sits an inch above the desk, and the height your fingers work at is thirty. If your seated elbow height is twenty-six, that desk at its very lowest still puts you four inches too high, exactly where Mara is now. A desk advertised as going down to twenty-eight inches did not lie to you. It just was not describing the number you needed.

Turn the same arithmetic around and you get the rule you will use when you shop. Take your measured elbow height, subtract the thickness of the top, subtract the height of the keyboard, and what is left is the highest the frame can be. Anything higher and you are back to shrugging, unless something else in the setup moves.

So write all of this down in one place, and keep it. A page in a notebook, a note on your phone, a file — it does not matter, as long as you can find it and add to it. Four body numbers, the current surface and seat and screen and space, the outlets, the clearance underneath. Then add one short list at the bottom: what your work actually demands. For Mara that is precision work with images, long typing sessions, frequent calls, and a wish to be less stuck in one position. Those demands are not decoration. Precision work argues for a stable screen and a pointing device you can control finely. Long typing argues for getting that typing height right before anything else. Frequent calls will matter later if there is ever a motor or a belt running in the room.

Now the free part. One change, nothing bought.

Mara's biggest measured gap is the four inches between her elbows and her table. The table does not move. So she moves. She puts a firm cushion on the chair, which raises the seat by about two and a half inches and lifts her elbows with it. Her feet no longer reach the floor properly from there, so she puts a two-inch stack of hardback books under them, flat and solid, and rests her feet on that.

Watch what happens to the arithmetic, because this is where people fool themselves. Once her feet are on the books, the books are the floor as far as her body is concerned. So we measure from the top of the books. Her elbows are twenty-six inches above where her feet used to be, plus two and a half from the cushion, minus two because her feet now start two inches higher. Call it twenty-six and a half inches above her new footrest. The table, measured from that same footrest surface, is twenty-eight. So the gap has gone from four inches down to about one and a half.

That is a real improvement and it is not a fix. I want to be plain about that. One and a half inches is still one and a half inches. Her wrists still ride up a little. Free adjustment got most of it and cannot get the rest, because the table is a fixed height and the chair only goes so far before her knees start hitting the underside.

Then the screen. She stacks books under the laptop and raises it six inches. The top of the picture goes from thirty-three inches to thirty-nine. Her seated eye height is forty-five, and we want the top of the active screen at or a little below eye level, so somewhere around forty-two to forty-five would be the sensible zone. Thirty-nine is closer than thirty-three. Her neck has less far to drop. It is still six inches short, and this is a small laptop screen, so short of the zone means real downward gaze.

And now the catch that this whole exercise exists to expose. On a laptop, the screen and the keyboard are one object. When Mara raised the lid six inches, she raised the keys six inches too. She has just undone the seat and footrest work and then some: her typing surface went from one and a half inches too high to seven and a half inches too high. You cannot fix both ends of a laptop by lifting it, because the geometry will not let you. There is one hinge and two problems.

The only way out is to stop treating them as one object. Lift the laptop and use it purely as a screen, then put a separate keyboard and a separate mouse or trackball down at elbow height. That is not a product pitch and I am not naming anything to buy. It is what the shape of the problem requires. Two things that need to be at two different heights need to be two things.

So Mara compromises for now. She lowers the laptop back down onto a smaller stack — a two-inch lift — which buys a little neck relief without wrecking the typing height, and she keeps the cushion and the books under her feet.

Then she works. This is the part people skip. An adjustment you have not tested is a guess. She writes a document for half an hour and takes one ordinary video call, and she checks four specific things.

Reach: can she get to the keys, the trackpad and her notebook without leaning or stretching? Mostly yes, though the shallow table means the laptop is closer to her face than she would like. Visibility: can she read the screen without dropping her chin? Better than before, not solved. Support: are her back and feet actually held? Yes — the books under her feet are the change she notices most, and her lower back stays against the chair now instead of sliding forward. Unwanted movement: does anything wobble? The cushion slides a little when she shifts, and the book stack under the laptop is not something she would trust with a heavier screen.

Two more things worth testing over a few days, because they only show up with time. Glare — where the light is, and whether the screen washes out at some hour of the afternoon. And changing position — whether she can shift how she is sitting now and then, instead of being locked into one shape, because holding any single posture for hours is its own problem.

So the record gets updated. Improved: foot support, back support, some neck angle. Not solved: typing height, still about one and a half inches too high with the compromise stack in place; screen height, still well below eye level; and the screen is too close, because a twenty-four-inch-deep table cannot easily put a display an arm's length away. Installed cost so far: nothing. That number is worth carrying forward as carefully as the others.

What to write down about your screen

Before anyone talks to you about mounting a display, there are four things you have to know about the display itself, and none of them are on the box in a useful form.

The first is its weight with the factory base taken off. Not the shipping weight, not the weight with the stand. Every mount's weight limit refers to the bare panel, so take the stand off, put the panel on a bathroom scale, and write down what it says. The second is its dimensions: width, height, the screen diagonal, and how deep the chassis sits — a strongly curved screen carries its weight further forward, which puts extra twisting force on a tilt joint. The third is the mounting pattern on the back: the spacing, center to center, of the four screw holes. The common standards are seventy-five by seventy-five millimeters and one hundred by one hundred, with two hundred by two hundred on larger panels. The fourth is whether those holes are recessed into a hollow in the back, or missing altogether. A recess means you need spacers to clear it. Missing holes mean you need a bracket made for that specific model.

Write those down next to your body numbers, and you can answer compatibility questions instead of guessing at them.

Now the question worth answering today, before any of that: does the stand or riser you already own reach where your measurements say the screen needs to be? This is arithmetic you can do in five minutes.

Measure the gap from the desktop surface up to the bottom edge of the screen, with the stand at its lowest setting, then again at its highest. Then measure the panel itself, bottom edge to top edge. Add the panel height to each of those two gaps and you have the lowest and highest that the top of the screen can sit above the desk. Add the desk height and you have it as a height off the floor, which is the form your eye-height number is in.

Run it on an example. Say Mara borrows a twenty-four-inch monitor. Its stand puts the bottom edge three inches above the desk at the lowest setting and eight inches at the highest. The panel is thirteen inches tall. So the top edge travels from sixteen to twenty-one inches above the desk. Her table is thirty inches, so the top of the screen can land anywhere from forty-six to fifty-one inches off the floor. Her seated eye height is forty-five, and we want the top at or two to three inches below that — call it forty-two to forty-five. Even at its lowest, that stand is an inch or two too high, and every inch of its adjustment range goes the wrong direction. The riser she was about to put under it would make things worse, not better. A stand that cannot go low enough is a different problem from one that cannot go high enough, and only the measurement tells you which one you have.

Depth deserves the same check. A comfortable viewing distance is roughly twenty to thirty inches, about an arm's length. A monitor pedestal or a laptop riser eats six to twelve inches of desk depth all by itself. On a table only twenty-four inches deep, a deep base shoves the screen forward into your face, and no amount of height adjustment fixes distance.

Be careful with the rule you have heard, that the top of the screen goes at eye level. It works on a modest screen for ordinary reading and it breaks in three situations. On a big panel — thirty-two inches and up, an ultrawide, or two screens stacked — putting the top bezel at eye level pushes the bottom half so far down that you crane to read it, so those need to sit lower, with eye level about a third to halfway down the panel. If your work lives at the bottom of the window, like a terminal or a timeline, the whole thing should sit lower for the same reason. And if you wear progressive or bifocal lenses, you read a screen through the lower part of the lens, so a screen at eye level makes you tip your head back all day. Those need to come down substantially — several inches below the usual placement — and tilt back a little.

I will say one thing about arms, and it is about why you cannot choose one yet. Arms have a minimum load as well as a maximum. The Ergotron LX Desk Mount, for instance, is rated for a working range of seven to twenty-five pounds and screens up to thirty-four inches, and it uses a mechanical constant-force spring rather than a gas strut. A light panel under that seven-pound floor will not stay put on it, and no headline capacity number tells you that. The other half of the decision is your desk: what the top is made of, how thick it is, whether the back edge is clear enough for a clamp, whether the underside can take a grommet. You need the panel's weight, the mounting pattern, and those desk facts in hand before the question is even askable. That is what the recording is for. When you are ready to compare, the current monitor arm comparison lives on the OCDevel site at the monitor arms page, and the desks are on the desks page.

Which brings us to the next thing actually worth measuring: a real desk's finished range, thickness of the top included, against the seated and standing typing heights you just wrote down. That comparison is where the frame-versus-desktop-versus-keyboard arithmetic starts paying you back.

For today, take your four numbers. Feet flat and supported, shoulders dropped, arms hanging, elbows at about a right angle. Floor to elbow and floor to eye, seated, and then again standing in the shoes you actually wear. Write them at the top of a page you can find again. Everything after this is decided by those four lines.