A circadian design assist tool to evaluate daylight access in buildings for human biological lighting needs

•A tool is developed to enable annual assessment of circadian daylight performance.•Integrates multi-spectral lighting components to calculate melanopic illuminance.•Facilitates modeling and evaluation of complex, multi-level projects.•Capable of assessing performance relative to WELL circadian lighting criteria.•A case study is performed to benchmark and compare 3 design alternatives.