Lower back pain at the end of a working day rarely arrives out of nowhere. It builds quietly through small things: a chair set a few centimetres too high, a laptop you've been craning towards since lunch, a mouse you reach for fifty times an hour with a twisted shoulder. None of it feels dramatic at 9am. By 4pm it does.
You don't need an expensive chair or a new desk to change how your back feels. You need a tape measure, a few books, and about twenty minutes. Work through it in order, from the ground up.
Start with your chair, not your desk
Almost everyone adjusts the desk first. Do the opposite. Your chair decides where your hips, knees and lower back sit, and everything else has to work around that.
Set the seat height so your feet rest flat on the floor and your knees are level with your hips, or slightly lower. If that leaves you too low for the desk, raise the chair and add something under your feet — a footrest, a sturdy box, a ream of paper. Dangling feet are a common reason people slide forward and sit with a rounded lower back, which is exactly the position most likely to ache.
Next, the seat depth. You want roughly two to three fingers' width between the back of your knees and the front edge of the seat. If the seat presses into the backs of your legs, you'll perch on the front edge instead of using the backrest.
Then the backrest. It should meet the inward curve of your lower back — the small of your back — not the middle of your shoulders. If it sits too low or too high, roll a small towel or a firm cushion and tuck it into the gap. This single change often does more than anything else on this list.
Finally, armrests. Lower them until your shoulders drop, or push them out of the way entirely. Armrests that push your shoulders up towards your ears create tension you'll feel by mid-afternoon.
Get the desk height right — and fix it if it's wrong
Sit back in the chair you've just adjusted. Let your arms hang, then bend your elbows to roughly a right angle. Your forearms should be parallel with the floor, or sloping very slightly down towards the keyboard, with your wrists straight rather than bent back.
If your elbows sit below the desk, the desk is too high — very common with dining tables. Raise the chair and use a footrest to keep your feet supported. If your elbows sit above the desk surface, it's too low; a fixed desk can be raised with sturdy blocks under the legs, provided it stays stable and you never lean your weight on the edge.
Then clear the space underneath. A box, a bag or a footstool in the way forces your knees to one side and twists your pelvis, which your lower back notices over a long day.
Screen and keyboard: small distances, big difference
The screen
Position the screen about an arm's length away, with the top of it roughly at eye level. If you wear varifocals or reading glasses, you may prefer it a little lower so you aren't tilting your head back to find the right part of the lens.
Laptop-only workers get the worst of both worlds: the screen is too low and the keyboard is too close. The fix is cheap. Put the laptop on a stand or a stack of books so the screen sits at eye level, and plug in a separate keyboard and mouse. If you only do one thing today, do that.
Keyboard and mouse
Bring the keyboard close enough that your upper arms stay by your sides. If you have to reach forward, you'll round your upper back and push your head forward, and the lower back usually follows.
Keep the mouse on the same level as the keyboard, right beside it rather than off to the side. If your mouse hand sits far out to the right, your shoulder and neck take the strain and you'll often end up sitting slightly rotated — a quiet contributor to one-sided lower back discomfort.
Change position more often than you think
There is no perfect sitting posture, only ones you can hold for a while. The back responds well to variety: the discs and the small muscles around the spine are fed by movement, and staying in one shape — even a good one — eventually gets uncomfortable.
Aim to change something every 20 to 30 minutes: stand up, walk to the kettle, take a call on your feet, or shift from the backrest to the front edge of the seat and back again. A routine you can do without leaving the room:
- Stand up and place your hands on your lower back.
- Lean backwards gently five or six times, only as far as feels comfortable.
- Walk for a minute — to the kitchen, up the stairs and back.
- Sit down again, feet flat, and reset your back against the lumbar support.
If you use a standing desk, treat it the same way. Alternating between sitting and standing through the day is more useful than standing all morning and sitting all afternoon, particularly in the first week while your legs adjust.
When the setup isn't the whole story
A better desk arrangement can ease a lot of everyday ache, but it isn't a treatment. If your pain is severe, keeps waking you at night, follows an injury, or comes with numbness, weakness or changes to bladder or bowel control, speak to a GP or another healthcare professional promptly rather than adjusting your chair again. For pain that has persisted for more than a few weeks, a physiotherapist or other qualified clinician can assess what is driving it. Setting up your workspace well is part of looking after your back, not a substitute for having it checked when something doesn't seem right.
Make the setup easy to keep
Nothing here needs to be perfect, and it doesn't need to be done in one sitting. Start with chair height and the rolled towel behind your lower back, because those two changes are free and take five minutes. Then deal with the screen, then the keyboard and mouse, then set a reminder to stand up twice an hour for the next week.
If you share the desk, note your settings on a sticky note or photograph the chair so you can restore them in seconds. A setup that takes ten seconds to put right is one you'll actually keep — and that's the one your lower back benefits from.
Photo: ClickerHappy / Pixabay
