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A seat cushion changes more than softness: it raises you by its thickness, which moves your elbows relative to the desk and lifts your feet off the floor. Of the three cushions we compared, the Cushion Lab is the thickest and largest (18 by 16 by 4 inches), the Everlasting Comfort is the middle option (17.3 by 14 by 3.15 inches) and the ComfiLife is the thinnest and adds a gel layer and a handle (17.5 by 13.7 by 2.8 inches). Use the tool below to see what each thickness does to your setup.
We have not tested these cushions. Sizes, weights and features come from the Amazon listings, checked on September 29, 2026. Several listings make pain-relief or doctor-recommended claims that we cannot verify, so we do not repeat them. This is general information, not medical advice.
What a cushion does to your height
If a cushion is 3 inches thick, your seat sits about 3 inches higher (a little less once the foam compresses). Your elbows rise by the same amount relative to the desk, and your feet may no longer reach the floor. OSHA says the entire sole of the foot should rest on the floor or a footrest, and that the back of the knee should be slightly higher than the seat (OSHA chair guidance). Enter your numbers.
Cushion effect calculator
Current seat height (floor to the top of the seat), cushion thickness, desk height and your height, in inches.
Planning estimates: elbows about 14 percent of your height above the seat, and the back of the knee about 25 percent of your height above the floor. Not a standard.
Three seat cushions compared
| Everlasting Comfort | Cushion Lab | ComfiLife | |
|---|---|---|---|
| Size L x W x H (as listed) | 17.3 x 14 x 3.15 in | 18 x 16 x 4 in | 17.5 x 13.7 x 2.8 in |
| Weight (as listed) | 1.5 lb | 2 lb | 2 lb |
| Fill (as listed) | 100 percent memory foam | Extra-dense charcoal memory foam | Gel and memory foam |
| Shape | U-shaped tailbone cutout | Contoured for thighs and hips | U-shaped |
| Cover and grip | Washable breathable cover, non-slip bottom | Not stated in the bullet points we read | Washable zippered velour cover, non-slip bottom, handle |
| Best for | A mid-thickness cushion with a cutout | A thick, large contoured cushion | A thinner cushion that adds less height |
The three lists give no firmness rating, and the listings that mention pain or sciatica relief are making marketing claims. Comfort depends on the person.
The three cushions
Everlasting Comfort Memory Foam Seat Cushion for Office Chairs
The listing describes a 100 percent memory foam cushion with a U-shaped cutout, a machine-washable breathable cover and a non-slip bottom. The table gives 17.3 by 14 by 3.15 inches and 1.5 lb.
- Good for: someone who wants a mid-thickness cushion with a cutout at the back.
- Keep in mind: at 3.15 inches it raises you noticeably, and the listing’s doctor-recommended and pain-relief wording is marketing we cannot verify.
Cushion Lab Patented Pressure Relief Seat Cushion
The listing describes an extra-dense charcoal memory foam cushion contoured to cradle the thighs and hips, intended for office chairs, cars and wheelchairs. The table gives 18 by 16 by 4 inches and 2 lb.
- Good for: someone who wants a larger, thicker contoured cushion on a wide, deep seat.
- Keep in mind: it is the thickest and largest of the three, so it adds the most height and may not fit a narrow or shallow seat. The bullet points we read do not describe the cover or grip.
ComfiLife Gel and Memory Foam Seat Cushion, U-Shaped
The listing describes a gel and memory foam cushion in a U shape with a non-slip bottom, a built-in handle and a machine-washable zippered velour cover. The table gives 17.5 by 13.7 by 2.8 inches and 2 lb.
- Good for: a thinner cushion that adds less height, and one you can carry easily.
- Keep in mind: the listing describes pain and sciatica relief, which is a claim we cannot verify.
How to choose a seat cushion
- Thickness first. It sets how much you rise. Use the tool above and check that your feet and elbows still fit.
- Size against your seat. A cushion longer or wider than the seat can slide or hang off. OSHA says the seat should support most of the thigh without pressing behind the knee. See our guide to numb feet in an office chair.
- Grip and cover. A non-slip bottom keeps it from sliding on a smooth seat. A washable cover is easier to keep clean.
- Not a fix for the wrong chair. If the seat is too high, too deep or badly shaped, a cushion hides the problem. See our lower back chair guide and ergonomic chair guide.
- Back support is separate. A seat cushion does not replace lumbar support. See our back support guide.
- Move regularly. OSHA says sitting still for long periods is not healthy, whatever you sit on.
Frequently asked questions
Do seat cushions help office chairs?
They can add softness and change the seat shape. They also raise you by their thickness, so check that your feet, elbows and desk still line up.
How thick should an office chair cushion be?
Thin enough that you do not lose foot contact or reach for the desk. The three we compared are 2.8 to 4 inches thick.
Does a U-shaped cushion help tailbone pain?
Listings claim so, but we cannot verify it. Persistent pain should be checked by a health professional.
Will a seat cushion fit my chair?
Check its length and width against your seat. A cushion that overhangs the seat can slide or press behind your knees.
Can a seat cushion replace a footrest?
No. A cushion raises you, which can leave your feet further from the floor and increase the need for a footrest.
Can I buy these seat cushions on Amazon?
Yes. All three link to their Amazon listings. Options and availability can change.
Specifications checked on September 29, 2026. Product details and availability on Amazon can change, so confirm size and features on the product page before you buy.
