Hotel attrition calculator for group room blocks
Enter your block one night at a time and see what a shortfall would cost — per night, where the exposure actually sits, and cumulatively, where it hides. Free, no email, nothing leaves your browser.
Your block, night by night
One row per night of the stay. Peak and shoulder nights usually carry different rates and very different pickup, which is exactly what an aggregate number hides.
What your contract says
Four clauses decide the bill. Every one of them is negotiable, and every one of them changes this number.
% you must fill — you may miss 20%.
The share of your shortfall you expect the hotel to resell and credit back. Nothing unless your contract says so.
% of the shortfall credited back.
Night by night
Where the exposure actually sits. A healthy cumulative pickup percentage routinely hides one soft shoulder night, and that night is the bill.
| Night | Blocked | Must fill | Picked up | Short | Exposure |
|---|---|---|---|---|---|
| Thursday (shoulder) | 15 | 12 | 12 | 0 | $0 |
| Friday (peak) | 30 | 24 | 28 | 0 | $0 |
| Saturday (peak) | 30 | 24 | 27 | 0 | $0 |
| Sunday (shoulder) | 10 | 8 | 6 | 2 | $378 |
| Total | 85 | 68 | 73 | 2 | $378 |
The same math, live
A calculator tells you what a block would cost. Blocks tells you what yours is costing.
Blocks reads the floor, the rate and the measurement basis off your signed contract and runs this calculation against live pickup, every night, for every hotel on the event. When a shoulder night starts sliding you hear about it while you can still release rooms or push names in — not in the final invoice.
Every figure carries what it is based on, in the same breath as the number: assumes 80% pickup, no attrition terms on file; no attrition clause on file; exempt, not your liability; commitment settled. A block that has been released or reconciled quotes no projected penalty at all, because there is nothing left to project.
What this calculator is doing
The floor, per night
Each night's contracted room nights times your minimum pickup percentage, rounded down, gives the room nights you must fill on that date. Anything below it is a shortfall, priced at that night's rate. Rounding down matters: 7 room nights at an 80% floor is a commitment of 5, not 6.
Per night versus cumulatively
The calculator computes both and shows you the one your contract uses, with the other underneath. On the seeded example — 15, 30, 30 and 10 rooms across four nights at an 80% floor — the block owes $378 measured per night and nothing at all measured cumulatively. Same block, same pickup, one clause apart. That is the number worth reading your contract for.
Peak and shoulder rates
Every night carries its own rate, so a shortfall on a $250 Saturday costs more than the same shortfall on a $150 Thursday. When the clause measures cumulatively there is no single night to charge, so the shortfall prices at the average contracted rate weighted by contracted room nights — and the calculator says so rather than quietly picking one.
Rolling release, resell credit, lost profit
Rooms handed back at a review date come off the block before the floor is applied, which is the whole reason to negotiate for review dates. A resell credit takes the rooms the hotel resold back out of your shortfall. And a group-favourable damages clause charges the rate less the hotel's saved variable cost — often around 75% — rather than full room revenue. All three are switches on this page because all three are switches in a contract.
What it cannot know
Whether your clause measures at arrival or at the cutoff changes which pickup number belongs in the grid, not how the grid is priced — so the calculator asks, relabels the column, and says which one it assumed. It does not model wash, it does not know your cancellation tiers, and it is business decision support rather than legal advice. The contract in front of you is the authority.
Hotel attrition, answered
The questions that decide whether the number above is the number you owe.
How do you calculate a hotel attrition penalty?
What is the difference between per-night and cumulative attrition?
Is attrition measured at the cutoff date or at arrival?
What is a resell credit worth?
Is this calculator free, and do you keep what I type?
Have more questions? Check our glossary of terms or get in touch.
Go deeper
How Blocks handles the jobs this work depends on — plus the terms and guides behind them.
Attrition tracking
Blocks tracks contracted and picked-up room nights by date and hotel, calculates the shortfall against your contract terms, and shows it while there is still time to act.
Learn more →Pickup tracking
Blocks tracks blocked, assigned, picked-up, and pending room nights for every date and hotel, flags where pickup is drifting from your block, and turns any view into a report you can export.
Learn more →Contract review
Blocks uses AI to pull rates, cutoff dates, and attrition terms out of your hotel contract in under 60 seconds, then reviews every clause against your negotiation playbook and hands you a ranked issues list — each flag quoting the exact contract wording.
Learn more →Key terms
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