How to Choose an Office Chair | Fit Over Features

Choosing an office chair comes down to adjustability: a chair only fits if you can tune its height, depth, and lumbar support to your body.

Most people pick an office chair by looks or brand, then live with back pain for a year. The actual rule is simpler: a chair is only ergonomic if it adjusts to fit you. For prolonged seated work, the chair should support your spine, let your feet rest flat, and keep your elbows close to your body with your shoulders relaxed, per Mayo Clinic guidance.

Below are the exact dimensions to check, the features that matter, and the mistakes that turn a “comfortable” chair into a backache.

Key Dimensions To Match Your Body

Standard ergonomic guidelines give a clear range for each measurement, but your body decides the final setting. The BIFMA G1-2013 and ANSI/HFES 100-2007 standards list these minimums and maximums for task chairs.

These numbers are a starting point. Try the chair at your actual desk before committing — a spec sheet can’t tell you how the seat edge hits your thighs.

Which Adjustments Matter Most?

Adjustable seat height is non-negotiable for foot contact and knee angle. After that, prioritize seat depth and lumbar support, because those two determine whether your spine holds a neutral curve.

• Seat height: set the top of the seat just below your kneecap, per the GSA’s adjustment guide.
• Seat depth: leave about a clenched-fist gap between the seat edge and the back of your knees.
• Lumbar support: position it in the 5.9–9.8 in zone above the seat, where your lower back curves inward.
• Armrests: set them so they barely touch the undersides of your elbows. If they force your shoulders up, remove them entirely — that’s the GSA’s explicit advice.

A chair labeled “ergonomic” means nothing if the lumbar pad sits too high or the seat pan is too deep for your frame. The adjustability range is the deciding factor, not the label.

What To Avoid When Shopping

The most common mistake is buying on upholstery or brand recognition instead of fit. A seat that’s too high leaves your feet dangling; one that’s too deep can reduce circulation behind the knees.

Armrests are the second-biggest trap. Most desks sit too high for standard armrests, which quietly lifts your shoulders toward your ears all day. If you can’t set them low enough, the GSA says to take them off — a chair without armrests beats a chair with wrong armrests.

Finally, don’t confuse durability with ergonomics.

Adjusting Your Chair Once You Have It

Fit is a two-step process: pick a chair with the right ranges, then set it for your body. Start with seat height — feet flat, knees level with your hips. Then set seat depth, then lumbar height, then armrests last, because they depend on all the others.

If your feet still don’t reach the floor after the seat is set, use a footrest rather than raising the chair and losing your knee angle. When everything lines up, your elbows should hang close to your body with your shoulders relaxed — that’s the success cue that the chair fits.

Once you know your measurements, the buying decision gets far easier. For a tested list of chairs that hit these ranges, see our roundup of the best chairs for office work.