Desworthy Editorial Team
Desworthy editorial reviewer focused on ergonomic chair research, desk tech, affiliate disclosure, and practical UK home office buying decisions.
Last reviewed on by Desworthy Editorial Team.
Last Verified Date: 6 October 2026. Sources and model-specific claims checked; individual fit and final basket totals depend on your circumstances.
AI Summary
- Seat width is not shoulder clearance: the C300 Pro's 51.56 cm published seat width and Pro V2's 52 cm width describe the seat. Source 2 Source 1
- Check the usable backrest width where your shoulder blades actually meet it, including when reclining.
- Reject a chair that pushes your shoulders forward or restricts normal arm movement.
Decision table
| Situation | Practical choice |
|---|---|
| Seller provides usable backrest width | Compare it with your shoulder-blade span, then sit-test. |
| Only overall chair or seat width is supplied | Request the missing backrest measurement before ordering. |
What to do
Wear your usual work clothing and check upright and reclined postures. A rear-view photograph can reveal whether side frames contact your shoulders, but comfort still needs a sit test. We found no comparable shoulder-clearance measurements across the Sihoo range, so a ranked list of models that "cause rounded shoulders" would overstate the evidence.
Ask for a backrest measurement at your contact height
Seat width, outside frame width and usable shoulder clearance should be recorded separately. Ask the seller to photograph a tape measure across the inner backrest at the height where your shoulder blades would touch, with the ruler endpoints visible. An overall width that includes the arms cannot answer this question.
| Dimension | Published UK figure | What it answers |
|---|---|---|
| C300 Pro maximum seat width | 51.56 cm | Seat-pan width, not shoulder room |
| C300 Pro V2 seat width | 52 cm | Seat-pan width, not inner backrest width |
| Pro V2 backrest height above seat | 52–60 cm | Vertical backrest positioning |
| Inner backrest width at your shoulder height | Request a measured photograph | Clearance at the actual contact point |
Figures come from the Pro specification and Pro V2 Tech Specs. In a trial, reach for the mouse and turn normally as well as sitting still. A chair that clears the shoulders at rest may contact them when the backrest flexes. Reject persistent frame contact that forces you forward; the table does not establish that one model prevents rounded shoulders.
Frequently asked questions
Can seat width stand in for shoulder room?
No. Those dimensions refer to different parts of the chair.
Does a manufacturer height range answer this?
No. People of the same height may have very different shoulder widths.
What if the headrest touches my shoulders?
If it changes your natural posture, treat that as a fit problem.
How do I buy without trying it first?
Get the relevant backrest measurement and written return costs before ordering.
Sources and citation notes
Specifications and policies are attributed to their original publishers. Named hands-on reviews are attributed to the reviewer and the version reviewed. The decision advice is editorial synthesis, not a clinical, laboratory or transaction result. Check the exact version and current terms before buying.
- [1] SIHOO UK C300 Pro specification
- [2] SIHOO UK C300 Pro V2 specification
- [3] HSE DSE workstation checklist
- [4] Tom's Guide, Anthony Spadafora, hands-on C300 review (2023)
Related UK buying guides
Note: This article is for reference only.