【Google Sheets】教你用Google試算表做甘特圖，進度管理更清楚

 https://www.marketersgo.com/marketing/google-sheets/202005/googlesheet-google-excel-ganttchart/

Google Sheet - Week number to Date

 =DATE(A1, 1, -3 + 7 * B1 - WEEKDAY(DATE(A1, 1, 4), 2) + 1)

A1: Year

B1: Week number