Why print a calendar with no dates
A blank calendar is a reusable grid. Teachers use an undated month for centers or behavior charts. Habit trackers use the same 7-by-6 frame every month. A family that reprints a week plan can keep a blank weekly template in a sleeve and write new dates by hand.
The undated monthly template still prints weekday headers. You choose Sunday start or Monday start, so the header matches how you number the month later. There are six rows, which is enough for any month, including those that need a sixth week.
The undated weekly template prints seven-day columns and writing lines. It does not lock you to a year. That is the point: the same PDF can serve next October and the October after that.
Because there are no numbers, holiday marks and event labels have nothing to attach to. Use a dated monthly calendar if you want Independence Day or a birthday printed in a cell. Use the blank grid when the handwriting is the content.
Print on Letter for U.S. copy paper. A4 works the same way. High contrast keeps empty cells easy to write in. Ink-saver gray is enough if you only need light rules.