What size desk do you need?

Desks are sold on width. It is the number in the product name, it is the first line of every spec box, and it is the thing people agonise over in the shop. It is also, of the two footprint dimensions, comfortably the less important one.

Width is a storage problem. You have things, they need to fit, you can measure them. Depth is a geometry problem, because your desk depth sets how far your screen can sit from your eyes — and unlike width, that is something published sources actually have numbers for. It is also the dimension you cannot fix later by tidying up.

This page is about the footprint only. Height is a different question with a different answer and its own arithmetic; it lives in the desk height calculator and we are not going to duplicate it here.

Depth is decided by viewing distance

Start with the one figure that constrains this. OSHA’s Computer Workstations eTool, verbatim:

“Generally, the preferred viewing distance is between 20 and 40 inches (50 and 100 cm) from the eye to the front surface of the computer screen.”

Read the measurement carefully, because it is easy to misapply. It is eye to the front surface of the screen. Not eye to desk edge. Not eye to the back of the monitor. And it is a range with twenty inches of latitude in it, which is a lot of room — OSHA is not being precious here.

ANSI/HFES 100-2007, the ANSI-accredited national standard for computer workstations, sets a floor from the other direction: its minimum design viewing distance is 40 cm. That is a design minimum rather than a recommendation — it is the closest a workstation should be built to allow, not a target.

The more interesting number is where people actually settle. HFES 100 reports that most users prefer viewing distances of 75–83 cm (29.5–32.7 in). Note where that sits: near the far end of OSHA’s 20–40″ range, and further awaythan the “arm’s length” rule of thumb that gets repeated everywhere. The folk advice pulls you closer than the preference data does.

Two honest notes on that figure. HFES attributes it to Sommerich, Joines & Psihogios (2001), and we read that citation inside HFES 100rather than in the original journal — so we are reporting what the standard says about the research, not what the research says itself. And it is a statement about what users prefer, which is a real, measured thing and not a claim that any distance is better for you.

Why desk depth is not viewing distance

Here is the step that gets skipped. Your desk depth is not your viewing distance, and the gap between them is bigger than people expect.

A monitor on its factory stand does not sit at the back edge of the desk. The stand has a footprint, often a deep one, and the panel sits somewhere above the front of it — so the screen is already some inches forward of the desk’s back edge before you have touched anything. Then subtract the distance between your eyes and the front edge, which is not zero either, because you sit back from the desk rather than pressed against it.

What is left over is your actual viewing distance, and on a shallow desk it can be a good deal less than the number on the box. This is why “my monitor feels too close” is usually a desk problem wearing a monitor costume. You cannot push the screen back past the wall, so the depth of the surface is a hard ceiling on how far away the screen can get.

We are not going to hand you a formula for this, because there is not a published one and the inputs are all yours: your stand’s footprint, how far back you sit, how thick your panel is. Measure it instead. Sit how you actually sit, and measure from your eye to the front of the screen. If that number is under 20 inches, the fix is depth — either more of it, or recovering some of what you have.

A monitor arm buys back depth

This is the real reason to consider an arm, and it is not the reason arms are usually sold. The marketing is about adjustability and desk tidiness. The geometry is about depth.

An arm takes the screen off its stand entirely. The mount clamps at the back edge, the panel hangs out over the desk, and the whole stand footprint you were paying for in inches simply disappears. On many setups an arm can also push the screen back pastthe desk’s rear edge, over the gap behind it — which means you can get a viewing distance a desk of that depth could not otherwise deliver.

Which reframes the purchase. If you are choosing between a deeper desk and a monitor arm on the desk you already own, those two things are competing to solve the same problem. That is worth knowing before you replace a piece of furniture. Our monitor arm roundup covers which ones publish the specs that decide whether an arm will hold your screen at all — the weight minimum being the one almost nobody prints.

An ultrawide constrains depth specifically

If you are running or planning an ultrawide, depth stops being a comfort question and becomes a fit question, and there is a published number for it.

HFES 100-2007 §5.2.4.3 says a screen should not “be located more than 35 degrees off axis (i.e., from the user’s predominant line of sight) while the user is gazing straight ahead”. On a normal 27″ screen at a normal distance that constraint is not doing much. On a very wide panel it is the whole problem: the far edges of the screen are a long way from your line of sight, and the only lever you have that brings them back inside the envelope is sitting further away.

Which is to say a wide screen needs depth in a way a tall one does not. Curvature helps — that is what it is for — but it does not repeal the geometry. So “can my desk take an ultrawide” is much less about whether the panel physically fits across the width, which it almost always does, and much more about whether you can get far enough back from it. The mounting side of that is covered in ultrawide monitor arms, and the same 35° envelope decides two-screen layouts too — see dual monitor ergonomics.

Width is decided by what actually goes on it

We looked for a published figure for desk width and there is not one. No standard we read specifies it, OSHA does not mention it, and we are not going to manufacture a rule to fill the gap. So width is an inventory exercise, and it is genuinely as boring as that sounds:

• One monitor and a keyboard. Needs the least width of any setup and is what most people actually run. If this is you, width is close to a non-issue and you should spend the decision on depth instead.
• Two monitors side by side.The main reason people need width, and worth checking against the 35° envelope above before you assume more width is the answer — two screens spread across a very wide desk is exactly how you end up turning your head all day.
• A laptop plus a dock and a main screen. The laptop wants its own patch of surface beside the monitor rather than in front of it, which is a real width cost people forget to count.
• Paper. If you actually write on paper, sign things, or spread a document out beside the keyboard, that is width nobody budgets for and everybody misses.

Measure what you own, lay it out on the floor if you have to, and add the room your hands need either side of the keyboard. That is your width. It is not a standards question.

The one real published number is underneath

Here is the honest state of the evidence on desk dimensions, and it is thinner than you would guess. The only figure OSHA gives about a desk at all is not about the surface. It is about the space under it:

“Clearance for the legs, under the desktop, should generally be between 20-28 inches (50-72 cm) high.”

Note what that is and is not. It is clearance— the vertical space your knees and thighs live in — and it is not the height of the desk. OSHA prescribes no desk height whatsoever, and anyone telling you it does is repeating something they have not checked. It is also, tellingly, vertical rather than a footprint number at all: the sum total of published guidance on how wide or deep a desk should be is that nobody has published any.

The related note from the same eTool is worth having, because it is the cheapest fix in ergonomics: “Remove center drawers of conventional desks to create additional thigh clearance if necessary.” If your knees hit something, the something is often a drawer you never open, and it usually comes out with a screwdriver.

What the real desks measure

For a sense of scale, here is what we could actually read at the source across the desks in our roundups — and the notable thing is how little of it there is.

Of the four desks we rank, two publish a surface size: the Vari Electric is 60 × 30″ and the VIVO 1B is 71 × 30″. That is a foot of difference in width and none at all in depth. The UPLIFT V2-Commercial has no published size because it is a frame— the top is your choice, which is either the best or the worst thing about it depending on how much you want to make decisions. And we could not read a published surface size for the Branch Duo at all.

Draw the obvious conclusion. Two data points is not a range, and we are not going to dress it up as one. What it does tell you is that 30″ is what the desks that publish anything both landed on, and that if you want depth beyond that you are into frame-and-top territory or you are buying a monitor arm to make the depth you have go further. Which of those is right depends on whether you enjoy choosing a desktop.

And if the desk you are looking at does not publish its dimensions, that is itself a data point about the manufacturer. The full picture of who publishes what is in the home office desk roundup.