Seat height
42.5 cm
16.7 in · 1′ 5″
Comfort band 40.5–44.5 cm
Free ergonomic tool
Chair Height & Seat Depth Calculator
Enter your height in centimetres or feet and inches. We estimate seat height from the back of the knee, and seat depth with a 2–3 finger gap so the chair supports the thighs without cutting circulation.
Recommended for 170 cm / 5′ 7″
Seat depth
42.5 cm
16.7 in · 1′ 5″
Comfort band 40.5–44.5 cm
Both settings fit a typical 40–54 cm chair with a 38–50 cm sliding seat.
- Armrests above the seat
- 36.6 cm · 14.4 in
- Matching sitting desk
- 69.7 cm · 27.4 in
- Knee clearance
- 2–3 fingers · about 6 cm
Specialised suggestions for you
- Seat height assumes socks or bare feet. Office shoes usually add about 2 cm — tick the shoes box or raise the chair by that on the first day.
- Set height first (feet flat, knees about 90°), then set depth so two to three fingers fit behind the knee. Lumbar support should meet the small of the back, not the belt line.
- Once the chair is right, set the desk to about 69.7 cm so elbows stay near 90°. The standing desk calculator will give sitting and standing numbers together.
- Armrests should sit around 36.6 cm above the seat — high enough to take the shoulders’ weight, low enough that you do not shrug. Drop them when they block you from the desk.
These figures are a starting point from standard adult proportions, not a medical assessment. If you have an existing injury, ask a physiotherapist or occupational therapist to check the setup.
How to set the chair
The illustration uses a 170 cm / 5′ 7″ person as an example: seat height around 43 cm (17 in) and seat depth around 42 cm (16.5 in), with a 2–3 finger gap behind the knee. Your numbers above replace those once you enter your height.
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1
Measure your height
Stand against a wall without shoes, heels together, looking straight ahead. Mark the crown of the head and measure to the floor in centimetres. The calculator also accepts feet and inches.
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2
Set seat height first
Sit all the way back. Raise or lower the chair until both feet rest flat and the knees are about 90°, thighs roughly parallel to the floor. If the desk then feels high, add a footrest rather than raising the chair until your feet dangle.
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3
Set seat depth
Slide the seat so you can fit two to three fingers (about 5–8 cm) between the front edge and the back of the knee. Too deep and the edge digs in; too shallow and the thighs lose support.
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4
Match the desk
With the chair set, raise the desk until the elbows sit just above the desktop. Use the standing desk height calculator for sitting and standing numbers, then set a monitor arm so the screen stays at eye line.
Ergonomic chairs with adjustable height and depth
Shop ergonomic chairs
Frequently Asked Questions (FAQ)
Seat height is the top of the compressed cushion to the floor. Seat depth is the usable pan from the backrest to the front edge. Convert centimetres to inches by dividing by 2.54 — the calculator shows both.
Sit back against the backrest. You should be able to slide two or three fingers between the front of the seat and the back of your knee. That gap (about 5–8 cm) stops the seat edge pressing on nerves and still supports the thighs.
Measure your body height without shoes. If you wear office shoes at the desk, tick the shoes option — it adds about 2 cm to the recommended seat height so your feet still sit flat.
A typical Australian office chair travels about 40–54 cm. That covers most adults. Users under about 160 cm may need a petite cylinder or a footrest; users over about 190 cm should look for a tall-cylinder model and a sliding seat.
Often yes. Slide the seat back or add a lumbar cushion to bring you forward until the 2–3 finger gap returns. Numbness that lasts should be checked with a clinician — this tool is a starting point, not a diagnosis.
Set the chair first, then the desk so elbows stay near 90°. A 170 cm person is usually around 43 cm seat height and 70 cm sitting desk height. Use both Joy Desk calculators together rather than copying someone else’s numbers.