The average length of stay for a patient admitted in mental health crisis to Manannan Court is 28 days.
Minister for Health and Social Care Claire Christian revealed the figure in a written reply to Tynwald.
However, Manx Care said it cannot provide an average cost for such a stay.
“This is because Manx Care does not currently utilise activity-based costing (ABC), a method that assigns overheads and indirect costs to specific services or activities and therefore cannot robustly attribute costs to an individual admission episode,” Ms Christian said.
The figures cover both Adult Acute and Older Persons admissions to the mental health unit. No breakdown between the two groups was provided.