How does the CSSE score calculator work?

It applies the formula the CSSE publishes each October: each raw mark out of 60 is standardised to a mean of 100 and a spread of 15 using that year's candidates, an age adjustment is added for each day the child is younger than 1 September, and the two are added and multiplied by 1.5. The means, spreads and age factors are the CSSE's own for the September 2025 and September 2024 tests.

Is the result my child's real CSSE score?

If you enter the raw marks from the CSSE test itself and choose that year, yes, to within rounding. If you enter marks from a mock or practice paper, the result is an estimate on the CSSE scale: the formula is right but the paper is not the CSSE's, so treat it as a guide to where the child stands, not a prediction.

What score does my child need?

It depends on the school and on which side of its priority area you live. The calculator compares the score with the last score offered a place at each of the seven Essex grammar schools in March 2025, inside and outside each priority area, and says how many more marks on either paper would close any gap.

CSSE Score Calculator: Raw Marks to Standardised Score, with Every School's Cut-Off

English markout of 60 Maths markout of 60 Date of birthfor the age adjustment Which testthe year's own figures Schools to showoptional

For a mock or practice paper, use the September 2025 figures: the formula is the CSSE's, the paper is not, so read the result as where the child stands rather than a prediction. The September 2026 test's own figures are published by the CSSE in mid October 2026 and will be added then.

What it is doing

The CSSE's formula, nothing else

The four steps

Each raw mark is standardised: (mark − that year's mean) ÷ that year's spread × 15 + 100. A mark on the average scores 100.
An age adjustment is added for every day the child is younger than 1 September of the cohort, using the factor the CSSE found that year (in 2025, 0.0166 a day in English and 0.0089 in Maths; in 2024, English only).
The two are added and multiplied by 1.5. An average child born on 1 September scores 300.
The total is set against the share of that year's candidates at or above it, from the CSSE's published list of every score, and against each school's last-offer score.

Where the numbers come from

The means, spreads and age factors are from the CSSE's 11+ Standardisation Report, October 2025 and the October 2024 report. The percentages are calculated from the CSSE's list of standardised scores for 2026 entry. The cut-offs are from the historical guidance sheet for offers made on 1 March 2025. All on the CSSE's Freedom of Information page.

If a figure here disagrees with the CSSE's, the CSSE is right and we will correct it.

Questions

Questions parents ask

Is this my child's real score?

If the marks are from the CSSE test itself and you choose that year, yes, to within rounding: the CSSE gives the total to two decimal places and rounds the cut-offs to whole numbers. If the marks are from a mock or a practice paper, the result is where those marks would fall on the CSSE scale; the paper was not the CSSE's, so it is a guide, not a prediction.

Why does English move the total more than Maths?

Because English marks bunch closer to the average (spread 7.6 in 2025) and Maths marks spread wider (13.1). One raw mark is one fifteenth of a spread, so an English mark was worth 3.0 points on the total in 2025 and a Maths mark 1.7. The calculator shows both, and says how many marks on either paper would close a gap.

My child was born in August. How much does the age adjustment give?

In 2025, up to about 14 points on the total for a child born on 31 August, and proportionally less for earlier birthdays. In 2024 it was English only, about 9 points at most. The calculator uses the year's own factor and shows the amount.

Which side of the priority area are we on?

KEGS is 12.5 miles from the school in a straight line; Colchester County High is 25 miles; the four Southend and Westcliff schools use postcodes SS0 to SS9; Colchester Royal Grammar has no area. The schools article explains each, with the number of places on each side.

Can I share the result?

Yes. Once you have worked out a score the address bar carries the marks and date, so copying the link reproduces the result. Nothing is stored on our side.

Want to know what those marks mean for the year ahead?

Book a free 20-minute call. Tell me the marks, the schools and where you live, and I will tell you honestly what the gap looks like and what would close it.

Book a free call