How to Adjust Office Chair Lumbar Support

Most advice on how to adjust office chair lumbar support stops at “put it at the small of your back.” That is true, and it is also why so many chairs sit with the lumbar wherever it shipped. The small of the back is a region, not a point, and the support has two settings that interact: how high it sits and how far it pushes forward. Get the height wrong by an inch and the depth that felt right becomes a fist. Below: the target measurement, the order to set things in, the controls on two common chairs, and the check to run after a long session.

The measurement: where the support has to land

OSHA’s workstation guidance puts it plainly: the outward curve of the backrest should fit into the small of the back, and lumbar support should be height adjustable so it can be placed to fit the lower back. The small of the back is the inward curve between the ribcage and the pelvis; on most people its deepest point is at roughly belt height.

The one field study that measured where office workers actually put an adjustable support is a lumbar-setting study (Ergonomics, 1998). They followed 123 office workers on identical chairs with lumbar adjustable in height and depth, recording settings four times over five weeks. Mean preferred height was 190 mm (about 7.5 inches) above the compressed seat. Mean depth, measured from the front of the seat to the lumbar support point, was 387 mm (about 15.2 inches). Two findings matter more than the means. Settings ran to both extremes of the adjustment range, so no single position suits everyone. And people with a higher body mass index chose a higher support, while standing height and sex made no difference. Subjects with recent chair-related back discomfort set the support deeper. Treat that as what people do, not a prescription: whether more curve suits a given back is a question for a clinician, not a knob.

Target: support centred on the inward curve, around 7 to 8 inches above the compressed seat for an average build and higher for a heavier one, at a depth that fills the gap without pushing you off the backrest.

Set seat height and depth first

Lumbar height is measured from the seat, so anything that moves the seat moves the target. Set seat height from the keyboard, then seat depth, then lumbar. The fitting sequence covers the first two, and the seat-height side is worked through on Home Desk Guide.

Seat depth matters more than it looks. If the pan is too long you cannot get your pelvis to the backrest, so you perch forward with the support touching nothing. The BIFMA G1-2013 fit test for seat depth asks for no undue pressure behind the knees, back properly supported by the backrest, and adequate buttock and thigh support. If your chair cannot meet that, no lumbar setting will be right, because you will never be against it.

Step by step: height, then depth, then recline

1. Sit all the way back: pelvis against the backrest, feet flat, hands on the keyboard. Do not brace into “good posture.” The chair should hold a neutral position; you should not have to.
2. Drop the support to its lowest position, then bring it up slowly. Stop where you feel it under the inward curve, at roughly belt height.
3. If there is a depth or firmness control, back it fully off, then add pressure until the gap between your lower back and the backrest closes. Contact, not push. Stop one step before it starts to tip you forward.
4. Unlock the recline and lean back. OSHA asks for at least 15 degrees of recline, and the BIFMA fit test says the back support should stay in contact with the lumbar area as it reclines. If the support loses contact or digs in when you lean back, it was set for upright only. Split the difference: recline tension decides the angle you actually spend the day at, and the lumbar has to be right there, not at showroom upright.
5. The hand check. Slide a flat hand between your lower back and the backrest. Goes in easily: too shallow or too high. Has to be forced: too deep.

Where the controls are on two common chairs

Steelcase Leap. Lumbar height moves by grabbing the two exposed tabs on the back and sliding the support up or down. Steelcase’s specification guide gives the range as 5 inches, from 5.25 to 10.25 inches above the seat (6.5 to 11.5 on Leap Plus), which brackets the study’s 7.5-inch mean with room either side. Lower back firmness is a knob that runs two complete turns, forward firmer, backward softer. It changes how much the flexing backrest resists in the lower region rather than moving a pad forward, so “deeper” on a Leap means “firmer.” A separate upper back force knob (five turns) controls how much support arrives as you recline; Steelcase’s framing is that the lower back needs firm, constant support while the upper back needs more as you recline. Seat depth slides 3 inches (15.75 to 18.75) on a handle under the seat; set it first.

Herman Miller Aeron. Two back options, adjusted differently. PostureFit SL is a pair of pads, lumbar above and sacrum below, driven by a knob at the back of the chair. Herman Miller’s adjustment guide says to turn the knob forward while seated to add pressure and backward to reduce it, and to set it with the tilt limiter engaged in the forward position, with your back in the pocket of the chair back. The Adjustable Lumbar Support option is a pad on a strap: raise or lower it with equal pressure on each end within its track, over a 4.5-inch vertical range. Neither option moves in and out; on an Aeron, depth is the PostureFit knob or nothing.

Most mid-priced chairs sold with “adjustable lumbar” offer one axis, a height slider or a depth knob, not both. One is better than none; skip the step you cannot do. What two-axis adjustment is worth before you buy is in how to choose an ergonomic chair, and ErgoRanker covers how to judge lumbar support from a spec sheet.

The 90-minute verification

Set it, work a normal ninety-minute stretch, and note where the tension is when you stand.

• Pressure or ache at the sacrum or tailbone: too low. Raise it.
• Being pushed forward, a hollow ache under the ribs, or sliding the pelvis forward to escape the pad: too deep. Back off one step.
• Ache between the shoulder blades and rounding over the desk: too high, or the recline is locked so upright that you hinge over the top of the support.
• Nothing in the lower back, but you keep leaning forward off the backrest: seat depth or armrest reach, not lumbar.
• The same low-back ache in the same place whatever you set: stop adjusting and read the last section.

CCOHS draws the line between firm lumbar support and pressure points that restrict circulation. A distinct spot you can feel after an hour is the wrong side of that line.

If the chair has no lumbar adjustment

A fixed contour is set for one body. The 1998 study concluded that fixed-height lumbar supports are unlikely to suit the range of potential users, and the spread in their data is why. If the whole backrest moves up and down, use that: the contour sits a fixed distance below the top of the backrest, so backrest height is your lumbar height.

An add-on pillow is the usual fallback, and the evidence is modest. A lumbar-pillow study (2013) had 28 men sit for 30 minutes with and without one. The pillow held lumbar lordosis about 2.9 degrees closer to neutral and improved a pressure-shifting measure, but self-rated comfort did not change significantly and the authors called the clinical relevance uncertain. A pillow cannot be set for depth repeatably, it migrates, and it usually sits too low because it rests on the seat pan. If you use one, strap it so its centre is at belt height.

What adjustment cannot do

A correctly set lumbar support gives a more neutral spine. It does not reliably remove sitting pain. A chair-design study (2023) ran 31 adults with no back pain history through four configurations of one chair, including a lumbar support condition. Lumbar support and seat-pan tilt produced the most neutral spine and pelvis, yet 39% of the sample still developed clinically significant pain during prolonged sitting whatever the configuration.

If you are adjusting a chair because of an existing back problem, the setting above is a starting point only. NIAMS lists pain that does not improve after a few weeks, numbness, leg weakness and pain after an injury among the signs to see a clinician. A chair setting diagnoses none of those. Get the diagnosis, then set the chair for it. For the interaction between seat depth, recline and desk clearance, use the chair adjustment checklist for lower back pain.

Related across the network

• How High Should a Standing Desk Be? The Elbow Height Method — ergoranker.com
• How to Fix Bad Posture at Desk: A Measurement-First Guide — ergoranker.com
• Best Desk Height for Ergonomics: How to Find Your Personal Ideal — homedeskguide.com
• Desk Chair Height: Set the Chair Before the Desk — homedeskguide.com
• Desk Ergonomics on a Budget: Healthy Setup Without Spending Much — homedeskguide.com