The Score measures improvement over QWERTY using fixed reference points. A score of 0% means the same as QWERTY, 100% means the theoretical best. Negative scores are possible for layouts worse than QWERTY.

Step 1: Normalize using QWERTY-fixed approach

Each metric is normalized using QWERTY as the worst reference and a fixed best value:

For lower is better metrics (SFB, SFS, LSB, Scissors, Redirect, Pinky), 0 is the best value:

$$\text{normalized} = \frac{\text{qwerty} - \text{value}}{\text{qwerty}}$$

For higher is better metrics (Rolls), 100% is the best value:

$$\text{normalized} = \frac{\text{value} - \text{qwerty}}{100 - \text{qwerty}}$$

Step 2: Apply weights

Each normalized value (already in "higher is better" form) is multiplied by its weight:

$$\text{contribution} = w \times \text{normalized}$$

Step 3: Calculate final score

The weighted sum is converted to a percentage of maximum possible improvement:

$$\text{score} = 100 \times \frac{\sum w_i \times \text{normalized}_i}{\sum w_i}$$

Note: This QWERTY-fixed approach ensures stable rankings — adding or removing layouts won't change the relative order of existing layouts. QWERTY's metrics are language-specific, so scores may vary by language.