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Sitting, sit bones and pressure.
Sit down and most of your seated weight lands on two small points of bone. These guides explain what happens there, how to measure the distance between them, and what that number means for any chair or cushion you buy. Plain language, and clear about what a cushion can and can’t do.
Start here
The anatomy, the measurement, and why the cushion is firm.
Sit-Bone Pain When Sitting: What’s Actually Happening
Why the ache shows up in the same two spots, why it gets worse on hard chairs, and what’s going on underneath.
ReadIschial Tuberosity: The Two Bones You Sit On
The two knobs you can feel under you on a hard bench, why so much of your seated weight funnels through them, and what that means for chairs and cushions.
ReadHow to Measure Your Sit-Bone Width at Home
A 60-second cardboard method for finding the distance between your sit bones — and what that number tells you before you buy a saddle, chair or cushion.
ReadSit-Bone Width for Bike Saddles (and Everything Else You Sit On)
Cyclists measure sit-bone width to size a saddle. The same number sizes a cushion. One measurement, two uses — and you already know how to take it.
ReadWhy Firm Beats Soft for Long Sitting
Soft cushions feel better for the first hour and worse by the sixth. The reason is compression — here is the mechanism, and when soft is the right answer.
ReadHow Far Apart Are Sit Bones? The Measured Numbers
Published measurements put adult sit bones 100–155 mm apart (4–6 in), wider in women and wider when you recline. What that means for a cutout cushion.
ReadSitting with a specific problem
Honest triage by condition — including when a cutout is the wrong tool.
Ischial Bursitis and Seat Cushions: Why Padding Fails and Offloading Works
The difference between cushioning a sore spot and taking the load off it entirely.
ReadHip Bursitis: A Chair Rarely Presses Where It Hurts
Most “hip bursitis” lives on the side of the hip, where sitting never presses — a one-minute check tells you whether yours is the rare sit-bone case where seat geometry even applies.
ReadHamstring Tendonitis Seat Cushion: What It Can and Cannot Change
The hamstring tendons anchor to the exact bone a chair presses on — why sitting flares this condition, and what a twin-opening cutout does and doesn’t change.
ReadPiriformis Cushion: Can a Cutout Reach the Pain?
Why a cutout cushion is usually the wrong buy for piriformis pain — and the one overlap case where the twin-opening geometry earns a look.
ReadTailbone Pain vs Sit-Bone Pain: One Spot or Two?
Slump back in your chair: one of these pains usually eases, the other gets worse. How to tell which you have, and which cushion shape it asks for.
ReadCompare and decide
Cushion against cushion, cushion against chair, and which Aylio cushion is yours.
Gel vs Memory Foam vs Cutout Seat Cushions
Gel spreads load, memory foam conforms, cutouts remove contact entirely. What each does over an eight-hour sit.
ReadWedge vs Cutout Seat Cushions: Two Different Jobs
A wedge changes your sitting angle; a cutout removes pressure from specific points. Which job your pain is actually asking for, and when you want both.
ReadAylio Coccyx Cushion vs Socket Seat: Which One?
Aylio makes both a U-cutout coccyx cushion and the twin-cutout Socket Seat. The honest decision rule between them, from the company that sells both.
ReadNew Office Chair or Seat Cushion First?
One costs several times the other, and the cheaper one is sometimes the wrong answer. How to tell whether your chair or your cushion is the real problem.
ReadSeat Cushions With Holes: What the Cutouts Do
Three different designs share the name. What each one removes, and how to check the spacing before you buy.
ReadDonut Cushion vs Twin Cutouts
A donut removes the whole center and hands your weight to the ring that remains. Twin cutouts remove two spots and keep the thighs supported.
ReadCoccyx Cushions: What the U-Shaped Cutout Is For
Where the U-channel sits, why the sit bones stay on foam, and when it is the wrong shape for the pain you have.
ReadTools
Fit Checker
Measure once with cardboard and get a straight answer on the Socket Seat’s openings, including “no”.
OpenSaddle Width Calculator
Sit-bone width and riding position, turned into a saddle width range with the published allowances shown.
Open1:1 Fit Template (PDF)
The two openings printed at actual size, with a ruler to catch a printer that scaled the page. Lay your cardboard on top.
PrintSit-Bone Measuring Card (PDF)
The cardboard method, the typical adult range and the saddle allowances on one sheet — free for shops and clinics.
Print
Know your sit-bone width? Check your fit.
Sit on a piece of corrugated cardboard on a hard chair or bench for 30 seconds. Stand up. Measure between the centers of the two dents.