An attrition clause sets the minimum percentage of your room block you must fill (typically 80-90%). If you fall short, you pay a penalty on unused rooms. Negotiate the percentage down, push for cumulative (not nightly) measurement, and include a resell clause so the hotel offsets rooms they rebook.
An attrition clause is a contract term that lets you release a percentage of your room block without penalty if fewer attendees book than expected. It is one of the most important protections in any hotel contract and one of the most negotiable.
Why Attrition Matters
When you sign a contract for 100 rooms, the hotel blocks those rooms off from general sale. If only 75 attendees actually book, the hotel still loses revenue on the 25 unbooked rooms. An attrition clause defines how much of that risk is shared.
With no attrition clause, you pay for 100 rooms regardless. With an 80% attrition clause, you guarantee 80 rooms — if fewer book, you pay the difference; if more, you pay only for actuals.
Standard Attrition Percentages in Europe
- Low-demand periods (January, August in business cities): 70-75% is often achievable
- Standard periods: 80% is the industry norm
- High-demand periods (trade shows, conferences nearby): 85-90% is common
- Peak events (major conferences, World Cup): 95-100% (effectively no attrition)
How Attrition Is Measured
Two methods exist, and which one you sign matters a lot.
Cumulative attrition: measured across the entire block over all nights. If you booked 100 room-nights total and filled 80, you are at 80%. This is favourable to the planner.
Night-by-night attrition: measured each night. If your block was 100/100/50 and you filled 90/95/30, you fell short on night three regardless of the other nights. This is favourable to the hotel.
Always negotiate cumulative attrition. Night-by-night schedules trigger penalties for even minor daily variation and are a common source of surprise charges.
How to Negotiate Attrition
Five levers, in descending order of impact:
- Commit to earlier cut-off date: Hotels accept softer attrition if you release unbooked rooms back to general sale earlier
- Accept resell credit: If the hotel resells your released rooms, you get credited for those
- Offer repeat business: Hotels will soften terms for planners who bring multiple events
- Lower the attrition percentage: Aim for 80% in standard periods
- Switch to cumulative measurement if they offered night-by-night
What Happens if You Fall Short
The hotel invoices you for the shortfall at the contracted rate, minus any resold rooms. For a 100-room block at EUR 180/night with 80% attrition, if you fill only 70 rooms, you owe 10 rooms × EUR 180 = EUR 1,800 per night of shortfall.
This is why attrition is the highest-variance risk in your event budget. A 10% attrition miss on a 200-room 3-night block can be EUR 10,000-15,000 of surprise spend.