Somebody needs to get City Hall a better calendar.

The Mayor’s office sent out a Friday night tweet reminding New Yorkers that early voting is starting on “Saturday, November 3.”

Early voting does begin a week from Saturday, but the date is Oct. 24. November 3, of course, is Election Day.

“Election Day is 18 days away!” the mayor’s office official twitter account wrote.

“Take some time over the weekend to make your voting plan. Early Voting starts next Saturday, November 3 and polls are open from 6 AM to 9 PM,” the tweet read.

Availability for early voting runs until Nov. 1. Hours vary by day, and polling sites for each borough are listed online by the city Board of Elections.

Next Saturday, sites across the city will be open from 10 a.m. to  4 p.m.

Commenters quickly pointed out the gaffe.

“Please post correct dates. This does more harm than good,” Twitter user Susan Kirby wrote.

Another user, David, wrote: “Please get this right. At least. Try again.”