How is school attendance calculated?
School attendance is calculated from the number of possible sessions available to a pupil and how many of those sessions they attended or missed. Schools normally take a register twice a day, so a full school day is usually two sessions.
In short
Attendance percentage = sessions attended ÷ possible sessions × 100
Absence percentage = sessions missed ÷ possible sessions × 100
Attendance and absence describe opposite parts of the same total, so the two percentages add to 100%.
What is a possible session?
A possible session is a school session during which the pupil was expected to attend. A pupil attending a normal full day would usually have one morning session and one afternoon session.
A 190-day school year therefore contains approximately 380 sessions, although the precise number of possible sessions for an individual pupil can differ. Official statistics use actual possible sessions rather than assuming the same figure for everyone. In autumn term 2025/26 the published data covered 989,466,742 possible sessions across 7,145,603 pupil enrolments in 21,215 schools.
A simple example
Suppose a pupil has had 200 possible sessions. They attended 184 and missed 16.
- Attendance rate: 184 ÷ 200 × 100 = 92%
- Absence rate: 16 ÷ 200 × 100 = 8%
How many days are missed at different attendance rates?
Using a 190-day school year purely as an illustration:
| Attendance | Approximate days missed |
|---|---|
| 100% | 0.0 days |
| 98% | 3.8 days |
| 95% | 9.5 days |
| 90% | 19.0 days |
| 85% | 28.5 days |
| 80% | 38.0 days |
These figures are illustrative rather than official individual calculations. A pupil's actual attendance percentage depends on their real number of possible sessions.
When does attendance become persistent absence?
Persistent absence is defined by the proportion of sessions missed, not by one fixed number of days. Once a pupil has missed 10% or more of their possible sessions they meet the statistical definition.
Over a complete 190-day school year that is approximately 19 days. Earlier in the year the number of sessions required to reach 10% is smaller, because fewer sessions have taken place.
Why do schools use sessions rather than days?
Sessions allow attendance records to reflect part of a day. A pupil may attend in the morning but be absent in the afternoon; recording two sessions gives a more accurate picture than treating the whole day as either attended or missed.
Can two pupils with the same number of days off have different attendance percentages?
Yes, if they have different numbers of possible sessions. One pupil may have joined the school later in the year, or have circumstances affecting the sessions for which attendance is expected. This is why official measures are calculated from each pupil's own possible sessions.
What the national figures look like
An overall absence rate of 6.47% is equivalent to an attendance rate of about 93.53% across the sessions represented in the data. It is a national aggregate, and is not a target for an individual pupil or school.
Explore the data yourself
See overall absence, persistent absence and severe absence across England, its regions and every local authority.
Explore school attendance →About this guidance
This page explains publicly available school attendance statistics and guidance for England. tutor2u uses Department for Education data and primary government guidance wherever possible. Every figure shown is calculated directly from the published DfE data files rather than transcribed by hand.
Attendance statistics describe patterns across pupils and schools. They should be interpreted with appropriate context and should not be used to make assumptions about the circumstances of an individual pupil.