When does the time limit change from 3 to 6 months?

For most claims, a time limit starting before 1 October 2026 is 3 months minus 1 day. If it starts on or after 1 October 2026, it is 6 months minus 1 day. The change does not extend earlier claims. Unfair-dismissal time runs from the effective date of termination; discrimination usually runs from the last discriminatory act included in the claim. Some claims have different limits, including a 7-day deadline for interim relief. Scottish breach-of-contract claims have a separate 9 November 2026 change: take advice on the applicable rules.

Does ACAS early conciliation extend my deadline?

If you notify Acas within the applicable time limit, early conciliation can extend it. The calculation excludes the period from the day after Acas receives your notification (Day A) to the day you receive the certificate (Day B), inclusive, and applies the statutory one-month-after-Day-B rule where relevant. These are not two extensions to add together. Late notification does not revive an expired claim. Dates can be complex: take advice if close to the deadline.

Can the deadline be extended?

Only in limited circumstances. For unfair dismissal, the tribunal can extend only if it was "not reasonably practicable" to file on time — a high bar. For discrimination claims the test is more flexible ("just and equitable"), but extension is never guaranteed.

What is the effective date of termination (EDT)?

For an ordinary dismissal, the EDT is normally the last day of the notice period or, if employment ends without notice, the date the termination takes effect. It is not necessarily your last working day or the date of your final pay. Statutory-notice extensions for some other purposes do not automatically extend the claim deadline. If the date is disputed, use the earliest plausible date and get advice.

I've missed the deadline. Is it over?

Not necessarily. Some claims, particularly discrimination, have more flexible extension rules. Take advice urgently — many employment law solicitors offer free initial consultations. If your ACAS certificate date was wrong, or you were given incorrect information about your rights, those can also be grounds to argue for an extension.

ET1 Deadline Checker — Calculate Your Tribunal Filing Date