The keypad is configured in an innovative staircase design with 3° inclination from right to left side. Compared to conventional desk calculators this causes less underarm torsion and hand wrist rotation as it adapts to natural finger / hand posture. The staircase key shape enables perfect vertical keystrokes and thus eases the key typing lessens burden and helps avoiding Repetitive Strain Injuries. The staircase design keypad causes less strain of the pronator teres muscle the extensor carpi radialis muscle and the flexor carpi radialis muscle