Save the Date
A pre-invitation sent 4 to 6 weeks before an event to block the date on guests' calendars.
A Save the Date is a short note, often a text, email, or postcard, sent 4 to 6 weeks before a graduation party to block the date on guests' calendars before the formal invitation goes out. It is not a full invitation. It contains only the host's name, the graduate's name, the date, and the city. No venue address, no RSVP, no dress code.
The point is to prevent the situation where guests later say "we would have come but we already booked something that weekend." For graduation parties in May and June, this is the single most important host action. May weekends fill up fast because most schools graduate in a 3-week window.
How to send: text or email works for under 40 guests. Paper postcard only for parties where older relatives or formal hosts expect it. Cost-conscious hosts send save-the-dates via Punchbowl or Paperless Post free tiers and skip paper entirely.
A typical wording: "Save the date, Sam graduates Lincoln High May 25, party that afternoon at the Lee house, formal invite coming." That is enough.