Tools for a lower seat
One calculator belongs on this desk. It converts a shoe-on popliteal height, or a barefoot stature plus heel, into a target seat height and a depth cap. If the target is under 16 inches, the next stop is the under-16-inch chair shortlist, not a second gadget.
Low seat height calculator
Uses the CCOHS quarter-stature preview, a 0.75 inch clearance, and the BIFMA 15.0 inch anchor as a check. A measured popliteal height overrides the preview.
The measurement steps live in the tape guide. The pillar for the number is low seat height under 16 inches.