Group Hotel Attrition: Calculate Minimums, Shortfall, and Damages

Estimate attrition risk and damages before you sign. Upload your nightly grid or enter totals to model cumulative or per-night minimums, allowed attrition, resell credits, and final penalties.

Planning a group stay is easier when the math is clear. This Attrition Calculator turns contract terms into simple numbers you can use and understand; showing minimum performance, allowable drop, shortfall, and estimated damages in seconds.

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What is hotel attrition?

Hotel attrition is the difference between the rooms you contracted and the rooms your group actually uses. Most group contracts allow a certain percentage of “slippage” without penalty. If your pickup falls below the minimum performance after that allowance, the hotel can charge damages based on the contract terms.

Attrition protects the hotel’s expected revenue while giving your group some flexibility. Your agreement will spell out the allowed attrition percentage, the method used to measure performance, and how damages are calculated.

How is attrition calculated?

There are two common methods:

• Cumulative: Compare total pickup to one minimum across the entire stay. Nights can offset each other.
• Per night: Each night has its own minimum. Shortfalls on one night are not offset by another night.

Typical damages are a percentage of the room rate used for damages. Contracts usually use the group ADR or a stated base rate. Some agreements allow a resell credit, which reduces your shortfall by the number of rooms the hotel resold.

Key terms you will see in contracts

• Allowed attrition %: The slippage you can use without penalty, for example 20%.
• Method: Cumulative or per night.
• Damages % and rate basis: The percentage to charge and which rate to use, for example 80% of group ADR.
• Resell or mitigation: Credit for rooms the hotel resold, sometimes capped at the shortfall.
• Cutoff and wash: Dates that allow you to reduce the block before penalties apply.
• Taxes and fees: Whether taxes or resort fees are included in damages. Many contracts exclude taxes from damages.

Quick example

• Contracted room nights: 200
• Allowed attrition: 20% → minimum performance = 160
• Pickup: 150 → shortfall before resell = 10
• Resell credit: 0 → billable shortfall = 10
• ADR used for damages: $179
• Damages percent: 80%
• Damages = 10 × $179 × 0.80 = $1,432

Planner tips

• Confirm the method. Per night is stricter than cumulative.
• Apply wash or cutoff reductions first, then measure attrition.
• Ask how resell credit is documented.
• Check if damages include or exclude taxes and fees.
• If your pattern shifts, revisit the block by night. Small moves can protect the minimum.

The math (clean formulas you can implement manually)

Cumulative method (single ADR)

• Contracted room nights = BBB
• Allowed attrition % = aaa
• Minimum performance = M=B×(1−a)M = B \times (1 - a)M=B×(1−a)
• Actual (or forecast) pickup = PPP
• Shortfall (before resell) = S0=max⁡(0,M−P)S_0 = \max(0, M - P)S0​=max(0,M−P)
• Resell credit rooms = RRR (if allowed)
• Billable shortfall = S=max⁡(0,S0−R)S = \max(0, S_0 - R)S=max(0,S0​−R)
• Group ADR used for damages = rrr
• Damages % = ddd (e.g., 0.80 for 80%)
• Damages = S×r×dS \times r \times dS×r×d
  • (Optionally multiply by tax if contract requires, but usually it doesn’t.)

Per-night method (rooms-by-night)
For each night iii:

• BiB_iBi​ = contracted rooms, PiP_iPi​ = pickup, rir_iri​ = rate
• Minimum Mi=Bi×(1−a)M_i = B_i \times (1 - a)Mi​=Bi​×(1−a)
• Shortfall si=max⁡(0,Mi−Pi)s_i = \max(0, M_i - P_i)si​=max(0,Mi​−Pi​)
• Billable shortfall after resell credit per night (if defined that way): si′s_i'si′​
• Damages =∑isi′×ri×d= \sum_i s_i' \times r_i \times d=∑i​si′​×ri​×d

Tiny worked example (cumulative):

• Contracted B=200B=200B=200, allowed attrition a=20%⇒M=160a=20\% \Rightarrow M=160a=20%⇒M=160
• Pickup P=150⇒S0=10P=150 \Rightarrow S_0=10P=150⇒S0​=10
• Resell credit R=0⇒S=10R=0 \Rightarrow S=10R=0⇒S=10
• ADR r=$179r=\$179r=$179, damages % d=80%d=80\%d=80%
• Damages =10×179×0.8=$1,432= 10 \times 179 \times 0.8 = \$1{,}432=10×179×0.8=$1,432
  If the hotel resold 20 rooms and the contract credits resell, R=20⇒S=max⁡(0,10−20)=0⇒$0R=20 \Rightarrow S=\max(0,10-20)=0 \Rightarrow \$0R=20⇒S=max(0,10−20)=0⇒$0 damages.

Per-night example (shows why method matters):
Block by night = 80 / 70 / 50; with 20% attrition → minimums = 64 / 56 / 40
Pickup = 70 / 50 / 30 → shortfalls = 0 / 6 / 10 → 16 total shortfall
Cumulative totals: block 200, min 160, pickup 150 → shortfall 10.
So per-night can be stricter than cumulative.

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