What room block attrition is
A hotel holds a set number of rooms for your group each night. If some of them stay empty, the gap is called attrition. Contracts usually allow some of it, say 20%. Fill at least 80% of the block and you pay nothing. Fill less and you pay for the empty rooms.
How many rooms were filled (the pickup) comes from the hotel’s report after the event, not from your registration list.
The allowance is negotiable. In the published contracts we reviewed, one Marriott hotel asked for 85% in total, and one Hyatt hotel asked for 80% on each day.
Attrition calculator
Enter your own numbers. The calculator shows both methods side by side. The difference between them is what’s worth negotiating.
You pay $0 with a cumulative clause and $4,000 night by night.
Night by night costs $4,000 more. That’s what a cumulative clause saves you. Free room nights earned: 7.
You need at least 280 room nights in total · This is an estimate. Taxes, rounding and credits depend on your contract. Not legal advice.
Cumulative or night by night?
The same 20% can be measured two ways, and the gap is usually bigger than people expect.
- Cumulative
- All nights are added up. A full night makes up for a short one.
- Night by night
- Each night is checked on its own. Extra rooms don’t carry over, so this is never cheaper than cumulative.
Example: three nights, $200 a night, 20% allowance.
| Night | Block | Minimum | Filled | Short |
|---|---|---|---|---|
| 1 | 100 | 80 | 110 | 0 |
| 2 | 150 | 120 | 100 | 20 |
| 3 | 100 | 80 | 95 | 0 |
| Total | 350 | 280 | 305 | — |
- Cumulative: 305 room nights filled, 280 needed. Nothing to pay: $0.
- Night by night: night two is 20 rooms short, and night one’s extra rooms don’t count. 20 × $200 = $4,000.
- If the hotel resells 5 of those rooms on night two, you pay $3,000.
How the penalty is calculated
The basic sum is simple: empty room nights × nightly rate. Contracts can soften it:
- Part of the rate. An empty room costs the hotel less to run, so some lawyers recommend paying 70–80% of the rate.
- Based on revenue. Expected room revenue is compared instead of room counts. Useful when the rate changes from night to night.
- No penalty if the hotel sold out. Some contracts waive it for nights the hotel was full. No empty rooms, no loss.
Whether tax is added and how numbers are rounded depends on the contract.
Credits that lower the bill
- Rooms the hotel resells. If the hotel sells one of your empty rooms to someone else, it comes off your shortfall. But most contracts treat your rooms as the last ones sold: while the hotel still has other empty rooms, yours don’t count as resold.
- Bookings outside your block. Some attendees book the hotel another way. Ask for them to be matched against your list and counted.
- No-show and early departure fees. If the hotel already charges for those nights, you shouldn’t pay a penalty on them too. That only holds if the contract says so.
Cut-off and review dates
On the cut-off date the hotel puts unnamed rooms back on sale. In the contracts we reviewed, it was 21–24 days before arrival.
Watch out: releasing the rooms usually doesn’t change what you owe. A room released at cut-off doesn’t drop out of the attrition count by itself.
Review dates are agreed points where you can shrink the block without a penalty. They are often worth more than a bigger allowance.
Free rooms and extra nights
Many contracts give you one free room night for every 40 or 50 paid ones. Unused free nights usually have no cash value.
Hotels often offer the group rate for a few days before and after the event. When guests use those nights, they usually count towards your pickup and free rooms. A food and beverage minimum is a separate commitment with its own terms.
Planned, actual and billable nights
Most attrition disputes come from treating three different numbers as one.
| Number | What it tells you | Where it comes from |
|---|---|---|
| Planned | The nights on the guest list | Your latest rooming list |
| Actual | The nights the guest really stayed | The hotel’s stay report |
| Billable | The nights you have to pay for | The contract, applied to actual stays |
Example: a guest is planned for three nights, Monday to Wednesday. They arrive a day late and leave a day early.
- Actual: 1 night.
- Billable: 3 nights, if the contract charges one night each for a no-show and an early departure. Under another contract it might be 1 night plus a flat fee.
- Pickup for attrition: still 1 night.
That’s why the three numbers need to be kept apart.
What to negotiate
- Cumulative instead of night by night
- Review dates and a penalty-free reduction
- Credit for rooms the hotel resells
- Outside bookings counted against your list
- No-show and early departure fees taken off the penalty
- The penalty as part of the rate, before tax
- No penalty on nights the hotel sold out
To track block and pickup night by night, use the room nights sheet in the free rooming list template.