Count your out-of-town guests, not your guest list. That is the whole method, and getting it wrong in the optimistic direction is how couples end up with an attrition bill on top of a catering bill.
The arithmetic
Take the guests travelling from far enough away to need a bed. Divide by two — most wedding rooms hold a couple. Then apply an honest discount for the guests who will book on their own no matter what you arrange: loyalty points, a rental with friends, a cheaper rate two exits down. For most weddings, the block that actually gets used is well under half of the travelling headcount in rooms.
So: 120 out-of-town guests is roughly 60 rooms of theoretical demand, and a 25 to 30 room block is a defensible contract. Blocking 60 because it feels generous is how you end up personally guaranteeing hotel occupancy on your own wedding weekend.
Courtesy block first, contracted block second
Many hotels offer a courtesy block — a held set of rooms with no financial guarantee, usually 10 to 20 rooms. If your count is anywhere near that range, take the courtesy block and skip the attrition clause entirely. Only sign a guaranteed block when the courtesy cap is genuinely too small, and even then, sign for less than you expect and add rooms as the RSVPs arrive. Hotels add rooms to a filling block gladly; they forgive empty ones never.
The guests the block will never serve
- The wedding party and close families often want a house together, not six hotel rooms on different floors.
- Groups of college friends split rentals by default.
- Budget-sensitive guests will book whatever is cheapest regardless of your negotiated rate.
Those guests are not a failure of your planning — they are just a different shape of demand. A lodging list that includes homes and nearby alternatives serves the whole guest list instead of the hotel-room half, and it keeps working after the block cutoff passes.
For venues that host weddings every weekend, this same overflow is a revenue line: guests book somewhere for every single event, and the venue that presents real options at RSVP time earns on bookings it currently sends to the booking sites for free.
Three real-shaped scenarios
A 150-guest wedding with 60 travelling guests: roughly 30 rooms of theoretical demand, of which perhaps half will use any block. A 15-room courtesy block covers it with no risk, and a house for the wedding party handles the group that was never booking rooms anyway. A 200-guest destination-style weekend where nearly everyone travels: now 80-plus rooms of demand across three nights — this is the rare wedding that justifies a contracted block, sized around 40 rooms with a reduction schedule, plus serious home inventory for families. A 90-guest hometown wedding with 20 travelers: skip the block entirely; a stays list with two hotels and a couple of rentals is the whole answer.
Notice what moves the answer: not the guest count, but the travelling share and the group shapes inside it. Count those two things from your RSVP list and the block sizes itself.
The questions to settle before calling hotels
- How many guests are travelling from beyond a comfortable drive home after the reception?
- How many will book as groups wanting a house — wedding party, college friends, extended family?
- What share of the remainder are loyalty-program or budget bookers who will ignore any block?
- Does the venue already have a stays page or partner that solves this without a contract?