What is the Knob Under My Office Chair for?

by Andrew Smith| Last Updated: March 10, 2022

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What is the Knob Under My Office Chair for

Probably, you just got a new office chair promising many adjustable aspects. Maybe it was the customer overly pleased with the reclining abilities the chair offered that sold you away. Maybe, you liked the comments about the sturdy footrest that didn’t budge a bit once set.

Upon looking underneath the pad to begin customizing your chair, you see many controls. Then, you wonder, “what is the knob under my office chair for?”

The knob under your office chair is either a tilt tension, height, back height, seat angle, or seat height adjustment control. Each works uniquely. For instance, tilt tension adjustment is a knob altering the rocking force. On the other hand, chair height adjustment works by lever position changes.

What is the Knob Under My Office Chair for?

Multiple controls underneath the chair’s seat pad allow you to change the seat’s height, alter its tension, adjust various height settings, plus more. Let’s see how to use the multiple controls under your seat.

Tilt Tension Control: What is Tilt Tension Adjustment?

This knob adjusts the chair’s tension. If you loosen the tension knob, the desk chair rocks easier. Twist the knob to the other direction to enhance the tension. Thankfully, the knob includes increment (+) and reduction (–) markings, so you know how to turn it.

If the knob is difficult to turn, twist it with a Channellock or wrench. Your chair’s tilt tension is often under the seat near the front and is the largest round knob. Nevertheless, some desk chairs feature little knobs or cranks on the side to adjust the tilt tension.

Height Change Control: How Does Chair Height Adjustment Work?

It’s disappointing when you buy an office chair that’s too high or too low. After some hours of sitting, your feet and legs ache. Hence, height adjustment is ubiquitous amongst office chairs. This knob lets you choose your ideal height.

The seat’s side has a height adjustment knob for easier access. If multiple knobs protrude, it’s usually the central one. To reduce the seat’s height, tug on it while adding weight. Pull the lever without weight on your chair to raise it.

The knob links to a pneumatic or hydraulic column beneath the seat. This metal shaft moves the seat up and down.

Back Height Adjustment

Sometimes, your office chair’s height is okay, yet the backrest is high or low? Maybe your desk chair’s backrest offers contoured support but isn’t at a suitable height.

If included, turn your back height control button to remove tension, then elevate or reduce the backrest to your liking. Stiffen the knob once you get your sweet spot.

Modern office chairs may have a ratchet rather than a knob for adjusting the back height. If so, place your hands at the backrest’s base and pull up. Each pull causes a click when the height pawl engages the ratchet.

To reduce, pull the backrest up until you hear no more clicks, then slide it down.

The ratchet technique has predetermined heights. So, you can’t rest your backrest in between two levels. Nonetheless, it’s easier to adjust.

Seat Angle Adjustment

Sitting for hours in an office chair requires proper posture, erect with an inclined spine. Even though your office chair’s backrest bulges, the seat angle is vital to maintaining good posture.

The seat angle control knob is the first one from the front. The seat’s front lowers as you turn this knob clockwise. If you turn it the other way, the seat’s rear drops.

Adjustable Seat Depth

If your desk chair has seat depth modification, you can find the perfect seat depth.

This knob is easy to find as it is the only control on the left. When you lift the knob, the seat moves forward and inward.

Correct seat depth helps with posture and back support. It also ensures good leg blood circulation.

If your knee’s backs press the seat, there may be pressure points preventing proper blood flow. On the other hand, backaches may result from keeping your knees far off the seat.

Keep a two-finger spacing between the rear of your knee and the seat’s front.

Related articles you might be interested to read:

How to Raise Office Chair Without Lever
How to Lock Office Chair Height


How Do I Use a Chair Tension Knob?

You use a chair tension knob by twisting it right or left. Should you need to make the desk chair easier to tilt, loosen the knob. If otherwise, tighten the knob to enhance tilt resistance.

What Does Tilt Lock Mean?

Tilt lock means to control that lets you position your chair at a specified angle. For instance, you can let your chair stay upright when you write or use your keyboard frequently. You may also lock your office chair in a slightly reclined position if your job isn’t as demanding.

What Are the Parts of a Desk Chair Called?

The parts of a desk chair are identified in various names, and there are nine main ones. These include:

  • Base: Provides stability
  • Mechanism: Allows adjustability
  • Seat pan: Where you sit
  • Cylinder: Attaches the base and seat pan
  • Armrest: Arm’s support
  • Headrest: Head and neck support
  • Backrest: Spine’s support
  • Wheels: Mobility
  • Footrest: Leg support


To recap, the answer to “what is the knob under my office chair for?” depends on:

  • The spot you are looking at
  • Your office chair design

While it’s often the tilt tension knob, it may be the height, backrest height, seat depth, or seat angle control.

Once you know these knobs, you can realign your chair for the best ergonomic setup you could get from it.