A chair is the one piece of office kit you’ll spend more time with than any other purchase, and most people choose one on colour, price and a two-minute sit in a showroom. That’s how a chair that felt fine at the time starts to feel wrong by the third week. The features below are the ones that genuinely decide whether you can work comfortably for a full day, and every one of them can be checked before you hand over any money. You don’t need to understand engineering. You need to know what to look for, and what to test.
Start With Seat Height and Depth
Everything else on a chair is secondary to where the seat puts your body. Set the height so your feet rest flat on the floor, your thighs are roughly level, and your hips sit slightly higher than your knees. Most gas lifts move through a range of around 45cm to 55cm, which suits a broad spread of heights, but if you’re short or tall, check the extremes rather than the middle. Someone around 1.55m may find a chair that won’t go low enough, and end up with numb feet or a desk that suddenly feels too high.
Seat depth matters just as much, and it’s the feature beginners ignore. Sit right back against the backrest, then check the gap between the front edge of the seat and the back of your knees. You want roughly two or three fingers of space. Any less and the edge presses into the backs of your legs; much more and you’ll slide forward to find support, which undoes the backrest entirely. If you’re at either end of the height range, a sliding seat pan — a seat that moves forward and back on runners — is one of the few upgrades genuinely worth paying for.
Lumbar Support and Your Lower Back
Your spine curves inward at the lower back, and a chair should fill that curve rather than flatten it. Look for lumbar support positioned so it sits in the small of your back, roughly level with your waist or just above. Height adjustment is the useful part, because it lets you move the support to the right spot for your body. Fixed pads that sit too low tend to push your pelvis forward and make you slouch, which is the opposite of the intention.
Depth adjustment — how far the support presses into your back — is a nice extra, but height matters more for most people. If you already have a diagnosed back condition or persistent pain, speak to a physiotherapist or your GP before choosing. A well-designed chair supports a good working posture; it doesn’t treat a medical problem.
Recline, Tilt Tension and the Backrest
Nobody holds one perfect posture for eight hours, and a chair that locks you rigidly upright will make you restless. What you want is a backrest that reclines slightly — around 100 to 110 degrees from the seat — plus a tension control that sets how much force it takes to lean back. Set too firm, the chair won’t move and you’ll fight it. Set too soft, and you’ll feel like you’re falling backwards every time you shift your weight.
A tilt lock is worth having too, so you can fix the angle when you need stability, for example while writing notes or on a video call. Backrest height is a personal choice: high backs suit people who lean back and want shoulder support, while mid-backs keep you cooler and usually cost less. If the top of the backrest digs into your shoulder blades, it’s the wrong shape for you.
Armrests and Shoulder Comfort
Armrests should let your shoulders drop and your elbows rest at roughly a right angle, with your forearms lightly supported. Too high, and your shoulders creep up towards your ears within an hour. Too low, and you’ll lean to one side to use them.
Height adjustment is the minimum you should accept. If you share a desk or type for most of the day, look for armrests that also move in and out, or swing sideways. One practical trap: check the armrests fit under your desk. If they don’t, you’ll either sit too far from your work or push the chair back and lose your back support. Flip-up arms solve this, as does removing the armrests altogether if the model allows it.
Materials, Foam and Breathability
Mesh backs let air move, which makes a real difference in a warm room or a south-facing home office. Cheap mesh can feel wiry against your back, though, so press on it before buying. Upholstered backs feel softer but trap heat.
For the seat, foam density matters more than thickness. A deep, soft cushion feels luxurious for ten minutes and then flattens, leaving you sitting on the base. Look for moulded, high-density foam and press the seat firmly with your palm — it should give slightly and spring back rather than collapse. On coverings, fabric breathes better, while leather and faux leather wipe clean more easily. If your budget is limited, put the money into the seat and mechanism rather than a premium covering.
The Base, Castors and Weight Rating
Underneath the chair, a few details separate something that lasts from something that wobbles:
- Five legs, not four. A five-star base is more stable and is standard on anything worth buying.
- Castors matched to your floor. Hard castors for carpet, softer ones for wood or tile, or glides if you’d rather the chair stayed put.
- A sensible weight rating. Chairs are tested to a maximum user weight. If you’re near or above the stated limit, choose a model rated higher, which usually means a stronger base and gas lift.
- A decent gas lift. Class 3 or class 4 cylinders are the more durable grades.
- A long warranty on the mechanism. Two years or more on the gas lift and tilt mechanism is a reasonable signal of build quality.
Test It Before You Buy
Five minutes in a showroom, or a careful read of the specification online, will tell you most of what you need to know. If you can sit in the chair, work through this:
- Set the seat height so your feet are flat, and check you can still reach the desk comfortably.
- Sit back and check the two-to-three-finger gap behind your knees.
- Lean back and adjust the tension until the recline feels controlled rather than springy.
- Move the armrests through their full range and check they clear the desk.
- Find every lever and control without leaving the seat.
Buying online? Check the seat height range, seat depth, weight rating and warranty before ordering, and buy from a retailer with a clear returns policy so you can send it back if it doesn’t suit. A chair that fits you properly will do more for your working day than any number of extras you’ll never adjust.
Photo: ricardorv30 / Pixabay
