Desks are built to one height. Bodies are not. That mismatch is why so many home offices feel almost right — fine for twenty minutes, quietly annoying by four o'clock, and genuinely sore by the end of the week.

The fix usually isn't a new desk. It's knowing one number: your seated elbow height. Measure it properly and you can judge any desk, chair or keyboard tray in seconds, and you'll know whether the problem is the furniture or simply how it's set up.

The measurement that matters: seated elbow height

A desk has one job: to support your forearms while your shoulders stay relaxed. Everything else — screen position, wrist angle, whether your feet touch the floor — follows from that.

Before you measure anything, set the chair. Sit with your back against the backrest, feet flat, and raise or lower the seat until your thighs are roughly horizontal, with knees level with your hips or a little below. That's the starting position, and it's why you should measure your elbows after sorting the chair, not before.

Then let your upper arms hang loose. Don't prop them on the armrests or hold them out. Bend one elbow to about 90 degrees, hand pointing forward, and measure from the floor to the bony point of the elbow.

Your desk top should sit level with that number, or up to about 3 cm below it. Slightly lower is usually better: it lets your wrists rest flat and keeps your shoulders from creeping upwards.

How to measure it in five minutes

1. Wear the shoes you'd normally wear at the desk, or decide you'll always be barefoot. Heel height changes the answer by a centimetre or two, and desks don't move.
2. Sit in the chair you actually use, back against the backrest rather than perched forward.
3. Adjust the seat height until your thighs are level and your feet are flat on the floor.
4. Let your arms hang. Bend one elbow to roughly 90 degrees.
5. Measure floor to elbow. Write the number down — a note on your phone is fine, but a strip of tape under the desk is better.
6. Compare it with your desk. If the desk surface is more than 3 cm above your elbow, the desk is too high for you.

If two people share the desk, measure both. Set it up for the shorter person where possible: a desk that's slightly low can be fixed with a footrest, but a desk that's too high pushes the shoulders up all day and is much harder to work around.

Typing height and reading height are not the same

Typing wants the keyboard flat or tilted slightly away from you, wrists straight rather than bent up or down, elbows at roughly 90 to 100 degrees and tucked near your sides. That's the position your elbow measurement is designed for.

Reading on paper wants something different. You naturally pull the page closer and drop your head towards it, which is the beginning of a stiff neck. A flat desk makes this worse, because the page sits low and far away.

Two ways to manage both:

• Set the desk for typing and bring reading up to you with a sloped document stand, a book stand or a clipboard propped against something solid.
• Add a clamp-on keyboard tray so the typing surface sits lower than the desktop. The main surface can then stay higher for writing, drawing or spreading out paperwork.

If you work on a laptop

A laptop forces a compromise: the screen and the keyboard are joined at a height that suits neither. Raise the laptop on a stand until the screen is comfortable, then use a separate keyboard and mouse at elbow height. It sounds fussy; it takes about a minute to set up and it's the single biggest improvement most home offices can make.

Where UK average heights land

Commonly quoted UK averages are around 175 cm for adult men and 162 cm for adult women. Treat those as background information rather than a personal answer — the spread within each group is far wider than the gap between them, and leg length varies independently of total height. Two people of identical height can need desks a few centimetres apart.

As a rough starting point, based on the elbow-height rule above:

• 155–162 cm: desk top around 65–69 cm
• 163–170 cm: around 67–71 cm
• 171–178 cm: around 69–73 cm
• 179–186 cm: around 72–76 cm
• 187 cm and above: around 74–79 cm

Notice how far these sit from the 73–75 cm that most fixed desks are built to. Someone around 160 cm is often working at a surface 6 cm too high, which is why the chair ends up raised too far, which is why their feet dangle. The desk was the problem all along, and the chair took the blame.

When the desk you own is the wrong height

If it's too high:

• Raise the chair, then add a footrest so your feet are still supported. Cheapest fix, biggest improvement.
• Fit a clamp-on keyboard tray so only the typing surface drops.
• If the desk has adjustable legs, lower it. If it's a solid top on bolt-on legs, shorter legs are sometimes available — measure carefully before ordering.

If it's too low:

• Use desk risers or sturdy blocks under the legs. Check the weight rating and give the desk a firm nudge afterwards.
• A thicker top or a riser frame under the existing one works, provided nothing wobbles.

For a shared desk, an adjustable-height desk is the tidy answer. Failing that, set the main surface for the taller person and the keyboard tray for the shorter one.

Four things to check once the height is right

• Monitor: top of the screen at or slightly below eye level, roughly an arm's length away. If it looks too low, that usually means the desk is too high relative to your chair.
• Feet: flat and supported. A stack of books or a box is a perfectly respectable footrest.
• Wrists: straight and floating, not resting on a hard front edge for long stretches.
• Movement: change position every 30 to 45 minutes. The best posture is the next one.

If you're getting persistent neck, shoulder or wrist pain, adjusting furniture is worth doing, but it isn't a diagnosis. Speak to your GP or a physiotherapist rather than rearranging your office indefinitely.

A two-minute check before your next session

Sit down, put your hands on the keyboard and run through it: feet flat, knees level, elbows at 90 degrees and close to your body, wrists straight, shoulders down, screen top at eye level.

Whatever fails that check, fix the cheapest item first. Nine times out of ten it's chair height plus a footrest, not a new desk. Then measure your elbow again — it's the number everything else hangs on, and it doesn't change.

Photo: DS stories / Pexels