Chair & Desk Sizer: Seat Height and Depth
Start with height-based estimates for checking a chair's adjustment range. Confirm seat depth, foot support and reach with your own seated measurements.
Tool assumptions: seat height = 0.25 × height, desk height = 0.41 × height, seat-pan depth = 0.23 × height. The depth calculation does not subtract knee clearance; check usable depth separately. Break reminders are selectable presets.
What to do with these numbers
These are starting points, not prescriptions. Bodies of the same overall height vary in leg length, so treat the output as the position to begin from and then adjust by feel.
CCOHS chair guidance describes one-quarter of body height as a rough seat-height estimate. The other multipliers are illustrative tool assumptions. For a general workstation-height calculation, use ErgoRanker's ergonomics calculator.
- Setting up a chair you already own? Work through the adjustments in order in the chair fit and specification checklist. Seat height is set from your keyboard, not the floor.
- Your chair will not reach the seat height above? Check the published adjustment range before buying anything else. Minimum seat height traps shorter sitters in particular, which is covered in how to choose an ergonomic chair.
- Seat-pan depth longer than your chair's fixed pan? That is the one specification you cannot correct after purchase without a sliding pan.
- Chair drifting below the height you set? That is a mechanical fault rather than a fit problem. See office chair keeps sinking.
Comparing a task chair against a gaming chair on these figures? The specification differences that matter are in ergonomic chair vs gaming chair.