I would use R. Phoneposting now but something like library(tidyverse) library(readxl) library(writexl) read_excel("file.xlsx") %>% group_by(group_i

I would use R. Phoneposting now but something like library(tidyverse) library(readxl) library(writexl) read_excel("file.xlsx") %>% group_by(group_id = row_number() %/% 20) %>% group_walk(~ write_xlsx(.x, paste0("file_", .y, ".xlsx"))) edit: updated to write xlsx instead of csv