Sep 1

Understanding Real, Planned, and Adjusted Class Sizes in Timetabling

At Escentral, we’re often asked about the difference between real, planned, and adjusted class sizes. Understanding these terms, and why each is used, is essential for anyone involved in university timetabling, space planning, or utilisation reporting.

In this article, we break down what each term means, why they matter, and how they fit together. 

Real Class Size

The real class size is the number of students actually enrolled on a module activity within the timetabling system.

This figure is what enables each student to see their personal timetable. It is also used for attendance monitoring. Because it reflects confirmed enrolments, it is often the most reliable of the three values.

The challenge is timing. Real class sizes are only known once students have enrolled, which typically happens after the timetable is built. This makes them unsuitable as the sole basis for timetable creation.

Some universities address this by allowing returning students to select modules before the timetable build begins. This best practice approach allows those module activities to be created and timetabled using real class sizes, providing higher-quality data. However, figures may still shift if students later change their selections.

For new (entry) students, real class sizes cannot be known in advance. Institutions therefore must rely on planned class sizes when building the timetable for at least some of their timetable activities (entry). 

Planned Class Size 

The planned class size is the estimated number of students for each timetabled activity.

How planned figures are set varies. In some institutions, course or module leads provide them, whilst others use advanced modelling techniques. Many rely on educated estimates, often based on previous years’ numbers adjusted for recruitment targets.

Because planned sizes form the basis of the timetable, accuracy here is critical. If the figures are off, problems arise:
  • Rooms may be too large or too small.
  • Too many or too few group activities may be created.
  • Late changes may be required, disrupting both staff and students.


Ultimately, the teaching estate must accommodate what is timetabled. In practice, this means planned numbers can drive estate requirements more so than real sizes.

Good practice: Once enrolments are complete, compare planned vs. real sizes at module level. Identify where the differences lie, trace back the causes, and adjust processes before the next timetable build. Institutions that continuously refine their process for determining planned data can right-size their estate, reduce inefficiencies, and improve the overall student experience. 

Adjusted Class Size 

Not every activity will have a real size recorded, for example, ad hoc activities such as meetings or events without direct student allocation. To ensure completeness, we use the adjusted class size.

The adjusted value is derived as follows:
  1. Use the real size where available.
  2. If no real size exists, use the planned size.
  3. If neither is available, use the room capacity, on the assumption that if a specific room has been booked, it is reasonable to assume the full space may be used.

This ensures that every timetabled activity has a class size value. 

Why Adjusted Class Size Matters

For timetable utilisation reporting, the adjusted class size is the most practical and reliable measure because it: 
  • Ensures no activities are excluded from occupancy or utilisation calculations. 
  • Provides a consistent, complete dataset. 
  • Uses the most accurate available value for each activity. 


Without this adjustment, gaps in the data would undermine reporting and reduce confidence in utilisation metrics. 

Final Thoughts

In summary: 
  • Real = the true number of students enrolled. 
  • Planned = the estimated number used to build the timetable. 
  • Adjusted = the complete dataset that fills in the gaps for reporting. 

A high-quality timetable dataset will contain a class size for every activity and only a narrow gap between planned and real values. Any missing or inaccurate figures represent opportunities to refine processes, improve the dataset, and strengthen the university’s ability to deliver both a cost-effective estate and a high-quality timetable. 
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