Under Desk Foot Rest: Does It Help?

An under-desk foot rest is a small platform that raises your feet while seated, and it can improve posture, reduce leg fatigue, and ease lower-back strain. You place it on the floor under your desk, rest your feet on it, and adjust the height and angle to keep your knees at roughly a 90-degree angle. This article explains how foot rests work, what to look for, and whether they are worth buying.

Formula

The calculator estimates the height of a foot rest you need by comparing your desk height, seat height, and body height. The formula is:

Foot rest height = Desk height − Seat height − (Your height × 0.25)

Where:

• Desk height (cm): the distance from the floor to the top surface of your desk.
• Seat height (cm): the distance from the floor to the top of your seat cushion when you sit on it.
• Your height (cm): your standing height.
• 0.25: an approximate factor for the length of your upper leg (thigh) as a fraction of your total height. This is a rough average; actual proportions vary.

The result is the vertical distance between the floor and the bottom of your feet when your knees are bent at about 90 degrees. If the result is negative, your feet already reach the floor comfortably and you likely do not need a foot rest.

Worked Example

Using the default values:

• Desk height = 75 cm
• Seat height = 45 cm
• Your height = 175 cm

Step 1: Multiply your height by 0.25: 175 × 0.25 = 43.75 cm (approximate thigh length).

Step 2: Subtract seat height and thigh length from desk height: 75 − 45 − 43.75 = −13.75 cm.

The result is −13.75 cm, meaning your feet would be 13.75 cm below the floor if you tried to keep a 90-degree knee bend. In practice, this means you are sitting too high relative to your desk, or your desk is too low. A foot rest of about 14 cm would bring your feet up to a comfortable position, but you may also need to lower your chair or raise your desk.

Why People Use Under-Desk Foot Rests

Most office chairs are designed for a 90-degree angle at the hips, knees, and ankles. When your feet do not reach the floor, your thighs press against the front edge of the seat, which can reduce blood flow and cause numbness. A foot rest fills that gap, letting your feet rest flat and your knees stay bent at a healthy angle.

Foot rests are also used to:

• Reduce pressure on the backs of the thighs and behind the knees.
• Encourage a more upright sitting posture, which can lower the load on the lower back.
• Provide a stable surface for fidgeting or gentle movement, which some people find helps concentration.
• Raise your feet to a level that matches the height of a footrest on a sit-stand desk when you are standing.

They are common in offices, home workstations, and for people who are shorter than average, but anyone whose chair is set higher than the floor-to-knee distance can benefit.

How to Choose a Foot Rest

Foot rests vary in size, material, and adjustability. Here are the key factors to consider:

• Height adjustability: Some models have a fixed height, while others have several tilt angles or a telescoping column. If your chair or desk height changes often, an adjustable one is more versatile.
• Surface angle: A flat rest is fine for most people, but a slight tilt (about 10–20 degrees) can reduce ankle strain and encourage a more natural foot position.
• Material: Hard plastic is durable and easy to clean; foam or gel tops are more comfortable for bare feet but may wear out faster. A non-slip base prevents the rest from sliding on carpet or hard floors.
• Size: A typical foot rest is about 45–50 cm wide and 30–35 cm deep. If you have long legs or like to spread your feet, a wider model may be better.
• Movement: Some foot rests have a rocking or tilting mechanism that lets you move your ankles and feet while sitting. This can help with circulation, but it may feel unstable to some users.

Try to match the foot rest height to your own measurements using the calculator above, and then test it for a few days. Most people adjust to a foot rest within a week.

Common Problems and Misconceptions

One common misconception is that a foot rest is only for short people. In reality, anyone whose chair is set higher than the floor-to-knee distance will have dangling feet. This can happen with thick seat cushions, adjustable chairs raised to match a tall desk, or for people with longer torsos and shorter legs.

Another issue is that a foot rest can feel like a barrier if you like to stretch your legs forward. Some users find that a foot rest gets in the way of getting up quickly. In that case, a smaller or a tilting model that can be pushed aside may work better.

A foot rest does not fix poor posture by itself. It only provides a stable base for your feet. If you still slouch or lean forward, you will still have back and neck strain. A foot rest is one part of an ergonomic setup that also includes a properly adjusted chair, desk, and monitor height.

Foot Rest vs. Other Solutions

If your feet do not reach the floor, you have several options:

• Foot rest: The simplest and cheapest solution. It raises your feet without changing your chair or desk.
• Lower your chair: If your chair can go lower, this is often the best fix. But if your desk is too high, lowering the chair may make your elbows sit below the desk surface.
• Raise your desk: If your desk is adjustable, raising it can allow you to raise your chair and keep your feet flat. This is the most complete solution but may not be possible with a fixed-height desk.
• Use a footrest on a sit-stand desk: When standing, a footrest can act as a small step to shift weight from one leg to the other.

In most cases, a foot rest is the easiest and most affordable option, and it can be used with any chair.

Safety and Comfort Tips

Using a foot rest is generally safe, but keep these points in mind:

• Make sure the foot rest does not slide away from you. A non-slip bottom or a rubber mat underneath helps.
• Do not place a foot rest so high that your knees are above your hips. That position increases pressure on the lower back.
• If you have circulation problems, varicose veins, or recent knee or hip surgery, check with a healthcare professional before adding a foot rest to your workspace.
• Take breaks and stand up regularly. A foot rest helps with seated comfort, but it does not replace the need to move.

Also, if you use a foot rest with a rocking mechanism, make sure it is stable enough to support your weight without tipping.

Frequently Asked Questions

Do under-desk foot rests really help with back pain?

They can help indirectly. By allowing your feet to rest flat and your knees to stay bent at 90 degrees, a foot rest reduces the tendency to slouch or sit on the edge of the chair. This can lower strain on the lower back for some people, but it is not a cure for back pain. If you have chronic back pain, you should also look at your chair, desk, and monitor heights, and talk to a doctor or physical therapist.

What height should a foot rest be?

The ideal height is the distance between the floor and the bottom of your feet when your knees are bent at 90 degrees and your thighs are parallel to the floor. You can estimate this with the calculator above, but the exact number depends on your chair height and your leg proportions. A good starting point is 10–15 cm, and then adjust up or down until your feet rest flat without pressure on the backs of your thighs.

Can a foot rest be used with a standing desk?

Yes, but in a different way. When standing, a foot rest can be used as a small step to place one foot on, which shifts your weight and reduces fatigue in your legs and lower back. Some people use a foot rest or a small stool specifically for this purpose while standing. It is not the same as sitting, but it can add variety to your standing posture.

Are expensive foot rests worth it?

Not necessarily. A basic, non-adjustable foot rest that is the right height can work just as well as a high-end model with multiple tilt angles and a gel top. The main things that matter are the height, a non-slip base, and a surface that is comfortable for your feet. Extra features like rocking or heating are nice but not essential for most people.

How do I know if I need a foot rest?

If you sit at a desk and your feet do not touch the floor, or if you find yourself tucking your feet under the chair or resting them on the chair base, you likely need a foot rest. You may also notice numbness or tingling in your feet or legs, or you may feel pressure on the backs of your thighs. If any of these apply, try a foot rest and see if the discomfort goes away.

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in h | Desk height (floor to top) | cm | 75 | 50 | 100
in s | Seat height (floor to top) | cm | 45 | 30 | 80
in u | Your height | cm | 175 | 120 | 210
out fr | Recommended foot rest height | cm | h - s - (u * 0.25) | 1