This estimator approximates operating-room case capacity from the number of rooms, staffed block hours, average case-room time, and a planned utilization factor. It is useful for testing how changes in room availability, schedule length, turnover-inclusive case time, or operating buffer affect the number of cases that can fit into a period.
The model is intentionally simple and does not optimize a surgical schedule. Case mix, surgeon availability, anesthesia coverage, turnover variability, emergencies, equipment constraints, and recovery capacity can all reduce realized throughput. Use the estimate as a first-pass capacity scenario.
Inputs
rooms
hr
hr
%
Result
—
Estimated case capacity
Usable room-hours—
Theoretical cases—
Cases per room-day—
1. Enter active operating rooms Count rooms available for the modeled surgical schedule.
2. Set staffed hours per room Use the number of hours each included room is staffed and supported.
3. Enter average room time per case Include the room-occupancy time appropriate for your planning definition, including turnover if that is how your data are measured.
4. Choose planned utilization Set the share of staffed room-hours you expect to allocate to cases.
5. Review whole-case capacity The headline rounds down because a partial case cannot normally be scheduled as completed capacity.
Theoretical cases = Operating rooms × Staffed hours per room ÷ Average room time per case
Planned case capacity = Theoretical cases × Planned utilization %
What the result means
The result estimates how many average cases fit into the modeled staffed room-hours at the selected utilization.
Real schedules contain different case lengths and constraints, so a discrete scheduling model may produce a lower or differently distributed case count.
Given: 8 ORs; 10 staffed hours each; 2.1 average room-hours per case; 85% utilization.
Result: 32 whole cases, using 68 planned room-hours.
Interpretation: At these averages, the modeled block can accommodate about 32 completed cases.
Should turnover time be included in case time?
Use a definition consistent with the room-hours you are allocating. If turnover consumes the same staffed room resource, include it in the average room-time requirement or model it separately.
Why does the calculator round down?
Capacity represents complete cases that fit in the modeled time. A fractional case indicates remaining time that may not be enough for another average case.
Can I use one average for all surgical specialties?
You can for a rough blended scenario, but specialty-specific or case-mix models are more reliable when procedure durations differ substantially.
Does this account for emergency add-ons?
Only if their time is already reflected in the utilization factor or average case time. Otherwise, reserve explicit buffer or model elective and emergency demand separately.
What else can constrain OR capacity?
Surgeon and anesthesia availability, nursing and technician staffing, equipment, sterile processing, pre-op, PACU, beds, and cancellation risk can all become limiting resources.