Typical timeframes
Four to six weeks: routine, task-level issues in junior or standardised roles, where progress is visible quickly (e.g. call-handling times, data entry accuracy, punctuality).
Six to eight weeks: mid-level roles where objectives involve behavioural change alongside task performance — client communication, collaboration, or quality of written work.
Eight to twelve weeks (sometimes longer): senior or specialist roles, or where objectives depend on cycles the employee doesn't fully control — a quarterly sales cycle, a project delivery milestone, or a role where meaningful output only appears every few weeks.
Why open-ended plans are a problem
A PIP with no end date, or one that says 'ongoing review', tends to drift. Employees report — and tribunals have found — that this creates prolonged uncertainty, which is itself a source of stress and can look like the plan was never seriously intended to end in success. Fix a duration when you issue the plan, even if you build in the possibility of a short, explicitly justified extension.
Checkpoints within the period
Break the total period into two or three checkpoints rather than one single meeting at the end. A six-week plan might have checkpoints at week two, week four and week six. Each checkpoint should look at the evidence since the last one, not restate the whole period from scratch — this stops recency bias creeping back in, which is exactly what a PIP is meant to prevent.
What justifies extending a plan
Extension can be reasonable where there's genuine, partial progress and a specific, short reason more time will help — for example, a training course that hasn't yet run, or a probationary employee who has only had two full sales cycles when three were needed to judge fairly. Extension is not reasonable as a way to avoid making a decision, or to keep someone in limbo. If you extend, put a new fixed end date on it and explain why in writing.
Interaction with probation periods
If the employee is still within a probationary period, check the contract: some probation clauses have their own extension mechanics, and a PIP timeframe that runs past the probation end date without an agreed extension can cause confusion about which process actually governs the outcome. Align the two dates explicitly rather than letting them run separately.
Frequently asked questions
Is there a legal minimum length for a PIP in the UK?
No statute sets a minimum. ACAS guidance simply expects the timeframe to be reasonable and proportionate to the role and the issue — long enough for a genuine, fair chance to improve.
Can a PIP be shorter than four weeks?
In principle yes, for narrow, fast-cycle issues, but very short plans (under two weeks) are more likely to be challenged as not giving a real opportunity to improve, especially for anything requiring behavioural rather than mechanical change.
What happens if the plan period ends and nobody's reviewed it?
Hold the outcome meeting on or close to the date you set. Letting it lapse silently is one of the more common process failures and undermines the credibility of the whole plan.
This is general guidance on UK workplace practice, not legal advice. If a case is contested, high-risk, or involves discrimination, ill-health or long service, take advice from a solicitor or ACAS before acting.
Next step
GoMediation.ai's PIP module sets dated checkpoints when the plan is created, so nothing drifts and every review happens on schedule.
Build time-bound plans automatically