Your calendar already knows when you worked. A timesheet is those events, for one week or month, with hours added up. Steps Export the week or month to a sheet (start, end, title, hours). Round each event the way you bill: up to 15 minutes, for example. Group by day or week with a pivot table. Remove events you declined or never answered. Google Calendar hours report by client If you track client work in Google Calendar, you can bill from it. You need a ...