Guidance

How to read your NCA report: special schools

Published 28 October 2026

Applies to England

Overview

This guidance describes the key features and figures of the net capacity assessment (NCA) report for special 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 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 number of places to generate a single net capacity figure.

The workplaces for special schools are initially based on the calculations for mainstream schools, but there are extra adjustments in the calculations to take account of:

• the significant additional space requirements of special-school pupils
• the wide variety of pupil needs

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 also shows 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 for 10 to 30 basic workplaces per room, or multiples of 30 in larger rooms, which may also contain additional resource workplaces. For special schools, these figures do not represent actual class sizes. A later adjustment in the calculation reduces the number of classroom workplaces to 35% of these figures.

Resource workplaces

Resource workplaces are used for support space and may include:

• offices
• storage
• break-out spaces

All rooms under 19.5 square metres in special schools only generate resource workplaces.

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

• spaces 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
  • 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 the number of sites and total site area
• main admissions details, including planned number of places
• nursery admissions details

Room details

This section 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 calculations

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 special schools, this is between 25% and 30% 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 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 is 90% of the maximum workplaces available
• capacity based on planned admission number (PAN) – this is the school’s planned number of places

The net capacity is equal to the capacity based on PAN (planned number of places) in special 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.

You can find more detailed descriptions of the net capacity method on the report itself in the net capacity assessment guidance.