Guidance

How to read your NCA report: secondary (mainstream)

Published 28 October 2026

Applies to England

Overview

This guidance describes the key features and figures of the net capacity assessment (NCA) report for mainstream secondary schools.

It explains the fundamental parts of the report and how the figures are calculated.

The net capacity assessment tool includes further information on the methodology and formulas used.

Summary

The report uses data on the size and type of every room in the school to generate a number of workplaces.

These are added up, and adjustments are made using a tried-and-tested formula to ensure the school also has enough space for non-teaching resources and facilities.

The adjustments also allow for limits on the number of pupils allowed in some teaching rooms for health and safety reasons and assume not all rooms are timetabled at all times.

This results in maximum and minimum capacity figures.

These are compared against the school’s planned admission figures and sixth-form numbers, to generate a single net capacity figure.

Sections of the report

Version control

This is used to show which version of the NCA tool was used to produce the report.

Guidance

This section explains the purpose of the report.

It provides step-by-step instructions on the sections in the report (tabs on the net capacity report Excel spreadsheet).

This section also includes definitions of the different types of room and other spaces in the school.

It goes on to show how the number of workplaces is calculated, using the size and type of each room.

The number of workplaces is broadly equivalent to the number of pupils that can be accommodated.

Basic workplaces

Basic workplaces are those that can be used for teaching.

The formula allows 15 to 30 basic workplaces per room, or multiples of 30 for larger rooms, which may also have additional resource workplaces.

Resource workplaces

Resource workplaces are used for support space and may include:

• offices
• storage
• break-out spaces

All rooms under 27 square metres only generate resource workplaces.

The guidance section also includes other useful definitions, such as:

• space that are unusable as basic workplaces and therefore do not count towards the capacity figure, such as those without enough light

• the status of each space, which determines whether the space is included in the capacity calculations. The status can be:

• a primary classbase
• teaching spaces
• early years and childcare spaces
• specially resources facilities for pupils with special educational needs and disabilities
• other ‘non-school’ spaces that are not normally available for teaching or learning
• blank or not applicable

Establishment details

These are important, as they are not just for reference. The following information is used in the capacity calculations:

• establishment age range
• building information, including number of sites and total site area
• main admissions details, including number of year groups and published admission number (PAN)
• sixth-form ‘staying on rates’ – sixth-form pupil numbers are collected for the current and previous academic year to provide an average ‘stay on rate’, which is used to generate an appropriate size of the sixth form
• nursery admissions details
• special educational needs admissions

Room details

This section can be useful, as it gives a complete list of the size, type and use of every room and space in the school.

This information forms the raw data that is used to make the capacity calculations.

Net capacity

This is the part of the report that shows the key elements of the net capacity assessment.

There is a definition for each box, which represents a figure used for the calculations.

The calculations include some adjustments depending on the size of the site and the type of school:

• the ‘utilisation factor’ is the average proportion of time that any workplace is in use – for secondary mainstream schools, this is between 67% and 75%, depending on the age range
• the ‘basic workplace allowance’ is an adjustment that recognises that smaller schools need some large non-teaching spaces and halls

The key numbers to look out for on this page are:

• maximum workplaces available: the maximum number of pupils that can be accommodated once the adjustments have been made to the total number of workplaces (to ensure there is enough space available for support areas and curriculum needs)
• minimum workplaces available: in mainstream schools, this in 90% of the maximum workplaces available
• capacity based on PAN: this is the school’s PAN multiplied by the number of year groups, plus sixth-form numbers

The net capacity is equal to the capacity based on PAN in mainstream schools, if it is within the minimum-to-maximum range.

If capacity based on PAN is below the minimum, the net capacity defaults to the minimum workplaces available.

If capacity based on PAN is above the maximum, the net capacity defaults to the maximum workplaces available.