A desk-ergonomics calculator can compare your measured workstation heights. It cannot calculate a medically ideal setup from your height alone. Measure seated elbow height and the keyboard surface, then use the difference as an adjustment question.
What the height difference calculates
Measured elbow height above floor = seat height above floor + elbow height above seat.
Keyboard difference = keyboard height above floor − measured elbow height above floor.
Example: 18 + 10 = 28 inches; 29 − 28 = +1 inch. A positive result means the keyboard surface is higher than the measured elbow level; a negative result means it is lower. Neither result is a clinical threshold.
Enter all dimensions in one unit system. Reject missing, nonnumeric, infinite, or negative dimensions; do not replace an unknown measurement with zero. A zero dimension is mathematically valid but should prompt a measurement check. Convert centimeters and inches before combining them: 1 inch = 2.54 centimeters.
Measure with the chair and support you actually use, relaxed arms, and the keyboard’s working surface rather than the desk edge. Recheck after a chair, keyboard tray, or footwear change. This arithmetic does not account for vision needs, wheelchair setup, injury, or all equipment constraints; a qualified assessment can be useful when the setup or symptoms are complex.
Enter and compare measured dimensions
| Question or field | Fictional completed example |
|---|---|
| Seat height in inches? | 18 |
| Elbow above seat in inches? | 10 |
| Keyboard above floor in inches? | 29 |
| Seated elbow above floor? | 18 + 10 = 28 |
| Keyboard difference? | 29 - 28 = 1 inch |
A worked situation: 18
Fictional example. The chair seat is 18 inches above the floor and the relaxed elbow is 10 inches above the seat. A keyboard surface at 29 inches is 1 inch above the measured elbow level. This is a dimension comparison, not a pain diagnosis.
Read the difference as a measurement
In the completed example, a seat at 18 inches plus an elbow 10 inches above it places the elbow at 28 inches above the floor. A keyboard surface at 29 inches gives a difference of +1 inch. That is a measured relationship, not a prescribed target or a diagnosis. Use the same units for all three measurements and do not substitute body height for the observed setup.
Clinical evidence relevant to desk ergonomics calculator
The ergonomics lens in HUMAN
Kerub places task, support, and movement in a systems-oriented discussion of daily use. The metaphor can organize workstation questions. It does not establish one ideal alignment, diagnose a compensation pattern from a photograph, or prove that posture caused a symptom.