Hotel Revenue Glossary · Forecasting
Wash Factor
The expected percentage of group block rooms that will go unused (not picked up by attendees). If a group blocks 100 rooms and historically 20% wash, the hotel expects only 80 actual arrivals from that block.
Why it matters: Wash factor is critical for accurate forecasting of group-heavy dates. Overestimating group pickup leads to turning away transient demand that could have filled those rooms. Underestimating leads to empty rooms and lost revenue.
Worked example: This organiser's conference blocks 60 rooms a night for three nights. The last four times they ran it they picked up 47, 44, 51 and 46 - an average of 47, so 21.7% washes. Forecast 47 a night rather than 60, and the 13 rooms a night you release back to transient at A$252 are worth 39 x 252 = A$9,828 across the block.
Common mistake: Applying one house-wide wash percentage to every block. A sports team whose rooms the club pays for barely washes at all; a conference where delegates book their own rooms against a block can wash 40%. Keep wash by organiser and by who pays, and re-forecast the block at cut-off rather than once at contract.