The most common parent question is also the most consequential — start too late and the runway is uncomfortably short, start too early and the child loses interest before the test that matters.
The honest answer
For most families, formal 11+ preparation begins in the spring of Year 5 — roughly eighteen months before the September of Year 6 sitting. This gives enough runway for topic work without forcing intensive practice at an age when most children are not yet developmentally ready for sustained timed work.
The footnote: "preparation" before Year 5 looks like reading widely, doing mental arithmetic in everyday life, and playing word and logic games. None of that needs to feel like school work.
Starting earlier than Year 5
Some families start in Year 4 or even earlier. There is no harm in early exposure if it is light-touch and game-like, but formal timed papers in Year 4 are usually counter-productive — the child either finds them too hard (knocking confidence) or too easy in a way that builds false confidence.
If you do start early, prioritise reading and vocabulary above all else. Vocabulary range built between ages five and ten is almost impossible to make up for between ages ten and eleven.
Starting later than spring of Year 5
Starting in summer of Year 5 is fine for most families. Starting in Year 6 itself is harder but not impossible — the key is ruthless prioritisation of the two weakest topic areas rather than attempting broad coverage.
A child starting in September of Year 6 has roughly four weeks before the live sitting in some areas, six weeks in others. With four weeks the realistic goal is format familiarisation rather than topic mastery.
A typical timeline by month
March of Year 5: baseline papers in each subject to identify weaknesses. April–June: focused topic work on the two weakest areas, fifteen to twenty minutes per day. July–August: full timed papers at fortnightly cadence, with the off-week dedicated to reviewing the marked paper.
September of Year 6: dress-rehearsal papers in test-day conditions, then a deliberate wind-down in the final fortnight. The week before the test should contain almost no practice at all.
Signs you are starting too late
If your child cannot complete a baseline paper inside the time limit by July of Year 5, the runway has compressed. This is not a disaster — it just means the next eight weeks need to be more focused than they would otherwise have been.
If your child cannot complete a baseline paper at all, regardless of time, the underlying skill gap is too wide to close before the live test. Have the honest conversation about whether the 11+ is the right route this year.
The question nobody asks
Should you do this at all? The 11+ is not the right path for every child, and a child who is reluctant in March of Year 5 is unlikely to be willingly engaged by September of Year 6. Better to make that decision early than to spend a year forcing a process the child does not want.
There are excellent comprehensive schools, excellent independent schools with later entry points, and routes into selective sixth forms at sixteen. The 11+ is one option among several, not the only road to a strong education.