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11+ age standardisation calculator

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

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  • Updates as you type
  • Data checked 26 September 2026
Which 11+ test
Year

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

11+ age standardisation

Choose a birth month

11+ scores are adjusted so younger children are not held back by age. See how much that was worth, from the published figures.

Exact for CSSE

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

Exact for CSSE only. Other areas adjust for age with their own tables, which we have not found published, so their numbers will differ.

CSSE standardisation reports; Buckinghamshire scores by birth month

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How we estimate

Scope, source, method, uncertainty, dates and what the answer can and cannot tell you.

What it covers

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.

Sources

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.

Uncertainty and limits

  • The CSSE figure is exact arithmetic from the published rule for that year. The allowance changes each year: for 2025 entry the maths paper had no age allowance, so the whole-year gap was 8.8 points against 14.0 for 2026.
  • The Buckinghamshire counts describe what happened after Bucks's own age adjustment. They are not a measure of the adjustment, and month-to-month differences of a few percent move from year to year.
  • Bucks files leave out the few children born outside the normal year group (30 for 2023 entry, 36 for 2024 and 41 for 2025).

Dates and versions

  • CSSE standardisation formula and published scores, 2024 to 2026 entry: data version 2026-09-26.1, checked 26 September 2026 (historical).
  • Buckinghamshire Secondary Transfer Test scores and qualifiers, 2023 to 2026 entry: data version 2026-09-26.1, checked 26 September 2026 (historical).
  • Page last changed 26 September 2026.

What the answer means

For CSSE the answer is how many extra points a birth month was worth for the same marks. For Bucks it is the share of children born in that month who reached 121. It cannot tell you how other areas adjust for age: test providers such as GL Assessment use their own tables, and we have found none published for Kent, Bexley or other areas.

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, checked 26 September 2026
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

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.

Sources

All 17 sources

CSSE standardisation formula and published scores, 2024 to 2026 entry: version 2026-09-26.1, First transcription from the 11+ research data, 26 September 2026. Buckinghamshire Secondary Transfer Test scores and qualifiers, 2023 to 2026 entry: version 2026-09-26.1, First transcription from the 11+ research data, 26 September 2026.

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