Posture Angle Checker
Check your hip, knee, and elbow angles against the neutral 90-90-90 seated posture rule and see exactly what to adjust.
Your posture check
The neutral "90-90-90" rule targets roughly 90–100° at the hip, knee, and elbow. Angles between 85° and 110° are treated as acceptable; anything outside that range is flagged.
Why three joint angles, not one number
Seated comfort isn't governed by a single measurement — it's the combination of hip, knee, and elbow angles working together. A chair that's perfectly set for your hips can still leave your elbows too low if the desk is wrong, or your knees too open if the seat is too high. Checking all three catches problems that a single-axis adjustment (like seat height alone) can miss.
If one or more joints fall outside the 85–110° window, treat it as a cue to revisit the related setup — seat height for hips and knees, desk height for elbows — rather than trying to force the angle by sitting differently.
Frequently Asked Questions
What is the '90-90-90' posture rule?
It's a simple reference for neutral seated posture: hips, knees, and elbows all bent to roughly a right angle — around 90 to 100 degrees. It's a starting benchmark for chair and desk setup, not a strict requirement your body must hit exactly.
What angle range does this tool treat as acceptable?
Each joint — hip, knee, and elbow — is checked against an 85 to 110 degree window. Angles inside that range are treated as fine; anything outside it is flagged with a note on whether the joint is too closed (angle too small) or too open (angle too large).
What does a 'too closed' hip angle mean, and how do I fix it?
A hip angle under 85 degrees usually means your seat is tilted forward or your torso is folded too far toward your knees — common with a chair that lacks recline or a desk that's too low, forcing you to lean in. Opening the seat-back recline slightly or raising the desk height can bring the angle back toward neutral.
What does a 'too open' knee or elbow angle mean?
An angle over 110 degrees at the knee often means your seat is too high relative to your leg length, so your legs extend out rather than bending comfortably; at the elbow it usually means your desk or armrest sits lower than your relaxed arm position. Check our seat height and desk height calculators for the matching adjustment.
Do I need exact goniometer measurements to use this?
No — a rough visual estimate (or a phone-camera photo checked against a protractor overlay) is enough for this kind of check. It's meant as a quick self-assessment to catch obvious setup problems, not a substitute for a professional ergonomic or physiotherapy assessment.
Educational estimate — not medical, physiotherapy, or occupational-health advice; consult a clinician or ergonomist for pain or medical needs.