Measuring Your Wall or Corner
A straight desk needs one wall run at least as long as its published width. Two desks side by side need both widths plus a walking gap between them, not just the widths touching. An L-shaped desk needs two walls meeting at a corner, each at least as long as the relevant published dimension.
One straight desk against a wall
Measure the wall run corner to corner, not just roughly - a desk that is an inch too wide for the space it was measured for by eye will not fit once it actually arrives. Compare that measurement against the desk's published width, with nothing else planned for that stretch of wall.
Two desks side by side
Take the 40 x 24 inch desk, at 40 in wide, next to the 55 x 24 inch desk, at 55 in wide. Side by side with a six-inch walking gap between them, they need 101 in of wall - more than the two widths added alone.
The gap is not optional if anyone needs to walk past the join between the two desks - a six-inch minimum is workable for a visual break, but more is needed if it also has to work as a walkway.
An L-shaped desk against a corner
This is a different measurement, not a bigger version of the same one: an L-shaped desk needs an actual corner, with a real wall on each side - one at least as long as the desk's published width, the other at least as long as its published depth. A wall with no adjoining corner cannot take an L-shaped desk regardless of how long it is.
What this does and does not tell you
This is the footprint check - whether the desk physically fits the room. It is a separate question from whether the desk's height range actually suits you; see the sizing pages for that check, computed for every desk in the range.
Questions
How much wall length does a straight desk need?
At least its published width, on one uninterrupted run.
How do I measure for two desks side by side?
Add both published widths together, plus a walking gap of at least six inches between them, and compare the total to the actual wall.
Does an L-shaped desk need the same wall length on both sides of the corner?
Not necessarily - check the desk's own published width and depth, which are usually different figures on this range's L-shapes.
Is footprint or height range the more common mistake?
Height range, in practice - a desk that never reaches the right height is wrong every day it is used, while a footprint mismatch usually shows up immediately at delivery. Both are worth checking; see sizing for the height-fit side of it.