The tRNA Adaptation Index (tAI) is a tRNA-centric measure of translation efficiency which includes weights that take into account the efficiencies of the different wobble interactions. To enable the calculation of the index based on a species-specific inference of these weights, we created the stAIcalc. The calculator includes optimized codons tAI weights for 100 species from the three domains of life along with an option to download a standalone software package that optimizes the weights for new organisms