Four terms, and the desk is the small one
Put a desk against a wall and the floor it consumes is not its depth. It is its depth plus the chair pulled out to working position, plus however much further the chair travels when you stand, plus whatever path you want behind that. At the defaults on this page — a 30 inch desk, 20 inches of pull-back, 16 more to stand, and a 30 inch walkway — the requirement lands at 80 inches against a 108 inch room, leaving 28 inches spare. The desk is 30 of that 80. The other 50 inches is air.
That is why swapping a 30 inch desk for a 24 inch one buys back six inches out of eighty and rarely rescues a room, while trimming the walkway from 36 to 30 buys the same six for free.
Standing up and passing behind are different requirements
Pushing your chair back to stand uses the floor behind you for a few seconds. Someone walking past while you work needs it continuously. Those two demands can share the same floor if they never happen together, and cannot if they do.
The page asks which case applies because it changes the arithmetic from a maximum to a sum. With nobody passing behind, the requirement is the larger of two figures: 80 inches for desk, chair and walkway, or 66 inches for desk, chair and the travel to stand up. The walkway wins, so 80 inches. With someone passing behind while you are pushed back, all four terms stack instead and the requirement becomes 96 inches. Sixteen inches of difference, from a question about who else is in the room.
The wall run has a fourth item too
Side to side, the tally is the desk, whatever return or second surface joins it, the cabinet or bookcase that ends up on the same wall, and the slice of wall you cannot use. That last one is the one that gets forgotten: a door swinging into the room takes a strip of wall out of service, and so does a radiator, a floor vent, a low window with a sill, or a run of trim you cannot push furniture flat against.
| Item | Default here | Running total on a 120 in wall |
|---|---|---|
| Desk | 60 in | 60 in |
| Return | 0 in | 60 in |
| Cabinet or bookcase | 18 in | 78 in |
| Wall kept clear | 30 in | 108 in |
| Left over | 12 in |
Measure the chair, do not estimate it
Pull-back is the term most often guessed and it varies a lot. A compact task chair pulled to a working position might sit its back 18 inches from the desk edge; a wide chair with a headrest and a reclined posture can be 26. That eight inches is more than the difference between the shallowest and deepest desks on the market. Sit at the desk you have, have someone measure from the edge to the furthest point of the chair, and use that.
Two hazards worth naming
Power and network cords crossing a walkway are the most common physical problem in a home office, and they are a trip hazard regardless of how the room is arranged. A desk fixed to a wall, or a wall-mounted shelf over one, is holding weight with whatever is behind the plasterboard, and drywall alone is not a fixing. Neither of those is something this page will give you a procedure for; both are worth knowing exist before the furniture is placed rather than after.
Questions people ask
How much walkway should I leave behind the chair?
This page will not tell you, because that is a number set by adopted building codes for regulated spaces and by preference everywhere else, and neither is something a calculator should assert. As a rough sense of scale, people describe about 24 inches as edging past sideways and about 36 as enough for two people to pass, but those are descriptions rather than requirements. Enter the figure you want and the arithmetic follows it. If the room is a workplace or a rental subject to rules, the requirement is whatever the authority having jurisdiction has adopted.
Why does the answer change so much when I say someone passes behind me?
Because it turns a maximum into a sum. If nobody passes while you are seated, the floor behind the chair does two jobs at different moments — you push back into it to stand, and you walk through it to leave — so the requirement is whichever job needs more. If someone passes while you are pushed back, both jobs need the floor at once and the depths add. At the defaults that is the difference between 80 inches and 96.
Does a corner desk help in a small room?
It changes which wall pays rather than reducing the total. A return running down the adjacent wall gives you more surface without adding depth on the first wall, but the second wall now has a desk depth plus its own clearance behind, which is the same stack rotated ninety degrees. The way to check it here is to run the depth stack twice, once for each wall, with the return length entered as the desk depth on the second pass.
What counts as wall I have to keep clear?
Anything you cannot put furniture flat against. A door swinging into the room is the big one, and the arc it sweeps is worth working out properly rather than eyeballing. Beyond that: radiators and baseboard heaters, floor and wall vents that furniture would block, a window whose sill sits below desk height, an electrical panel, and any run of trim, pipe boxing or return-air grille that stops a cabinet sitting flush. Add them up and enter the total.
Is the room depth measured to the wall or to the baseboard?
To whatever the furniture actually touches, which is the baseboard on most rooms. That is typically half to three quarters of an inch of lost depth per wall, and it is why a desk measured to fit exactly does not. The same applies to a chair reaching a far wall: it stops at the trim. Take the measurement at the tightest point along the run, since walls in older houses are rarely parallel and the calculator has no way to know which end you measured.