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ElevenPlusGenius

11+ age standardisation calculator

In the CSSE 11+ for 2026 entry, the youngest child in the year got 14.0 more points from age standardisation than the oldest with the same marks.

Which 11+ test
Year

CSSE publishes its age allowance, so this is exact for its test.

11+ age standardisation

Choose a birth month

Your result

Pick a month to see every month of the school year side by side.

Questions people ask

What is age standardisation in the 11+?

It adjusts scores so that children are compared with others of the same age. The youngest children in the year, born in the summer, would otherwise be at a disadvantage of almost a year.

How many points does a summer birthday add in the CSSE?

For 2026 entry, a child born on 31 August got 14.0 more points than one born on 1 September with the same marks; for 2025 entry it was 8.8 and for 2024 entry 10.1.

Do summer-born children pass the Bucks 11+ less often?

In the published files the differences are small and change from year to year. For 2025 entry, 39.3% of August-born children reached 121 against 39.4% of the year group; for 2023 entry, 36.9% against 36.8%.

Does the Kent Test adjust for age?

Kent's scores are age-standardised, but we have found no published table of the adjustment, so this tool gives no figure for it rather than guess.

The data story behind this tool

Keep going

How we work this out

What it does

See how many points a birth month was worth in the Essex CSSE 11+, and how Buckinghamshire results compared by birth month.

Two 11+ tests that publish enough to answer this. Essex (CSSE), 2024 to 2026 entry: the age allowance in its standardisation reports. Buckinghamshire, 2023 to 2025 entry: every child's score by birth month, for children born in the normal year group.

Method

  1. CSSE adds a fixed number of points for every day a child is younger than 1 September: 1.5 x (the English allowance + the maths allowance). For 2026 entry that is 1.5 x (0.016617 + 0.008943) = 0.0383 points a day.
  2. For your month we multiply by the days from 1 September to the first and to the last day of the month. May is 242 to 272 days, so 9.3 to 10.4 points for 2026 entry.
  3. To make points easier to picture, we divide by what one English mark was worth that year (22.5 divided by the English spread): 2.96 points for 2026 entry.
  4. For Buckinghamshire we count, for each birth month, how many children scored 121 or more, from the published score files.
  5. The one number shown is the middle of the range across the days of your child's birth month.

Published figures

CSSE extra points by birth month

Points added for the same marks, compared with a child born on 1 September, on the last day of each month. Calculated from CSSE’s published age allowances.

From CSSE's standardisation reports
Born in2026 entry2025 entry2024 entry
September+1.1+0.7+0.8
October+2.3+1.5+1.7
November+3.5+2.2+2.5
December+4.6+2.9+3.4
January+5.8+3.7+4.2
February+6.9+4.4+5.0
March+8.1+5.1+5.8
April+9.2+5.9+6.7
May+10.4+6.6+7.5
June+11.6+7.3+8.4
July+12.8+8.1+9.2
August+14.0+8.8+10.1