Skip to Content
To Ergonomics is reader-supported. When you buy through links on our site, we may earn an affiliate commission. Read more.

How to Measure Seat Pan Depth?

How to Measure Seat Pan Depth?

Most of us don’t know what the seat pan depth is or why it is significant, but I assure you that it is essential. Most ergonomic chairs are equipped with adjustable seat pan depths and it is important to know the proper depth for your posture and comfort.

Seat pan depth is measured from the back of the seat pan to the end of your inner thigh or the back of your knee. You can use a tape measure to check the length. A rule of thumb to find the proper seat pan depth is to set the end of the seat pan two to four fingers from your inner knee or about two to three inches.

What is the seat pan depth?

The seat pan depth is the distance from the back of the seat pan to your inner knee or the end of your inner thigh.

Seat-Pan-Depth

Seat pan depth is not to be confused with the width or length of the seat pan. These dimensions are also significant for comfort, but the seat pan depth is distinct from the length and width.

The seat pan depth is crucial for proper positioning of your back and legs. Your overall posture can be improved by having the proper seat pan depth. The proper seat pan depth allows your back to rest against the backrest and your knees to be bent at a ninety-degree angle with the floor while leaving a few inches between the end of the seat and your inner knee.

The most critical part of measuring the seat pan depth is the measurement between the end of the seat pan and your inner knee (or end of your inner thigh).

How to measure the seat pan depth of an office chair?

To measure the seat pan depth, the user must sit in the seat and measure from the back of the seat pan to the end of their inner thigh (back of the knee).

ROSA | Chair Seat Pan Depth Assessment

As the video shows, the person using the office chair must be the one sitting in the seat while measuring the seat pan depth. Each person will have specific measurements based on their body.

The following is a step-by-step guide to measuring the seat pan depth of your office chair.

  1. Sit on your office chair.
  2. Make any necessary adjustments to the backrest and seat pan height.
  3. Make sure your feet are set firmly on the floor.
  4. Position your back against the backrest.
  5. Make sure your knees are bent at a ninety-degree angle with your feet firmly on the floor.
  6. Check the distance between the end of your seat and your inner knee. You can measure this by using a measuring tape, ruler, or using your finger width. The distance between the end of your chair and your inner knee should be about two to three inches or two to four finger widths.

What is the best seat pan depth?

The best seat pan depth is between 14” and 18.5” for most people. Those measurements are based on the best seat pan depths of a large sampling of people. With that in mind, outliers or people will fall outside of these numbers.

The best seat pan depth will be based on the individual. A better way to measure the best seat pan depth for you is by checking the space between the end of the seat pan and your inner knee. That will give you a better approximation of your seat pan depth.

Check seat pan depth

The best seat pan depth is the depth that allows you to sit properly. The best ergonomic seating position places your back against the backrest with your knees bent at a ninety-degree angle and your feet planted firmly on the floor or footrest.

If the seat pan depth is not long enough, your knees will be too far away from the end of the chair. This puts extra pressure on your knees and a small portion of your thigh. The seat pan will “dig” into the thigh, causing pain.

If the seat pan depth is too long, the end of the seat will put pressure on your inner knees. This will cause discomfort and decrease the blood flow to your feet. Poor blood flow to your feet can cause pain in your heels and feet, and other medical problems over time.

Also, if the seat pan depth is too long, you may not be able to effectively use the backrest, which can cause back pain and spinal issues over time.

For those reasons, it is important to know how to adjust your office chair to the correct depth.

How to adjust the seat pan depth of my office chair?

Most ergonomic office chairs have a handle, knob, or button on the seat’s lower right side, which you would pull up and then slide your seat pan to the desired depth.

How to Adjust Your Office Chair Seat Depth Correctly

You can adjust the seat depth while seated in the chair to easily check to see if you have positioned it properly. You can also do this while standing or kneeling next to the chair and then checking it by sitting and measuring the distance between your seat and your inner knee.

If your office chair does not have an adjustable seat depth, there are very few options.

If the space between your seat and your knee is too short, you can add a back cushion. The back cushion will allow you to rest your back against the cushion while creating more space between your seat and knee.

If there is too much space, you may try a seat cushion that is just slightly longer than the office chair seat pan. This may give you enough support under your thigh while keeping your knees in the proper position.

seat cushion

If your office chair is not adjustable, your best bet is to spring for a new adjustable office chair; your body will thank you.

Summary

The seat pan depth is an important part of sitting ergonomically at the office. The seat pan depth is the length from the back of the seat to the back of your knee. Each person will have to find the proper length for their body.

The best seat pan depth is the depth that provides two to three inches (two to four fingers) between your knee and the back of the seat pan.

Most ergonomic office chairs have a lever, button, or dial that makes it easy to adjust the seat pan depth. If your chair does not have an adjustable seat pan depth, it may be time to invest in a new office chair.

Now that you know what the seat pan depth is, how to measure it, and how to adjust it, you should know what you’re looking for if you purchase a new office chair. If you already have one, maybe you just learned how to adjust it properly. Whatever your situation is, we hope you better understand the importance of the seat pan depth and will work more comfortably, effectively, and healthier!