The metrics used are those from the CHEM21 reaction assessment, excluding metrics (purification method, catalyst recovery, and all yield-based metrics) that cannot be applied before the experiment is carried out. The temperature, solvent, stoichiometry, element sustainability, atom economy, and safety are all assessed based on the predicted route and conditions. Each reaction is individually assessed on these metrics, and each value is color-coded. Every reaction in a route can also be color-coded by taking a weighted median of the metrics, where sustainable is equal to 1, problematic 2, hazardous 3, and highly hazardous 4. Each metric has a corresponding slider that the user can assign between zero and ten; if the weights are all equal, it operates as an ordinary median. The total sum of weights is calculated, and the median or 50 th percentile weight is found.