This an R package including a shiny app to help users to estimate the time required to complete a systematic review or systematic map.
Please see this paper for more details of the methods used to develop this tool.
Haddaway NR, Westgate MJ. Predicting the time needed for environmental systematic reviews and systematic maps. Conserv Biol. 2019 Apr;33(2):434-443. doi: 10.1111/cobi.13231. Epub 2018 Oct 24. PMID: 30285277.