Room-Block Sizer
Use this room-block calculator to size a hotel block that covers your out-of-town guests without leaving you on the hook for empty rooms. Enter the out-of-town attendee count, the share who'll need a room, how many will share a room, your arrival and departure spread, and a realistic pickup rate. The tool returns a recommended block size, total room-nights, and your attrition exposure if you over-commit. These are planning estimates; your contract's attrition clause sets the real penalty.
Everything runs in your browser. None of the numbers you enter are sent anywhere.
- Rooms you'll likely fill
- —
- Attrition-safe floor
- —
- Exposure if you over-commit
- —
Planning estimate. The recommended block is sized to expected pickup; the attrition-safe floor is the lowest you can fall to before penalties under the allowance you entered. Confirm the clause in your contract.
Common questions
How big should my hotel room block be?
Size it to the rooms you'll actually fill, not your full guest list. Start from the out-of-town attendees, take the share who'll book a room, adjust for people sharing, and discount by a realistic pickup rate. Booking for the whole headcount is the fastest way to owe attrition on rooms nobody slept in.
What is room-block attrition?
Most contracted blocks allow you to fall short of the committed room-nights by a set percentage, often 10 to 20 percent, before penalties apply. Drop below that allowance and you pay for the unsold rooms. This tool estimates your exposure if your pickup comes in under what you committed.
Should I use a courtesy block or a contracted block?
A courtesy block holds rooms with no attrition liability but no rate guarantee and the rooms can be released. A contracted block locks the rate and the inventory but puts attrition on you. As a rule, contract only the room-nights you're confident you'll fill and leave the rest as a courtesy block or overflow.
Ready for real numbers? Get quotes from venues
Tell us the basics and we'll connect you with up to three matching venues. Free, no obligation.