Guide · Time limits

ACAS early conciliation, explained

Before almost any employment tribunal claim can be started, ACAS has to be told about the dispute first. This guide explains what early conciliation is, what the certificate does, what "Day A" and "Day B" mean, and exactly how notifying ACAS pauses the tribunal time limit.

What early conciliation is

Early conciliation is a free process run by ACAS (the Advisory, Conciliation and Arbitration Service), a public body that is independent of both sides. Its purpose is to see whether a workplace dispute can be settled by agreement before a tribunal claim is issued.

For most types of claim, notifying ACAS is not optional: a tribunal claim generally cannot be presented without an early conciliation certificate number on the claim form. Telling ACAS about the dispute is, in practice, the first formal step of the tribunal process.

Notification is done through a short form on the ACAS website or by phone (0300 123 1100). It asks for basic details — who you are, who the employer is — and does not require you to set out your case.

What happens after you notify

An ACAS conciliator contacts you, and (if you agree) the employer, to explore whether settlement is possible. Some points people are often relieved to learn:

You don't have to settle. Conciliation is voluntary in substance — either side can decline to engage, and you can end the process at any time and ask for your certificate.
It doesn't judge your case. The conciliator is impartial and does not advise either side or decide who is right.
It has a time limit of its own. The conciliation period lasts up to six weeks. If no settlement is reached — or either side ends it early — ACAS issues the certificate.

The certificate, Day A and Day B

The early conciliation certificate is the document that proves the requirement has been met. It carries a number, which goes on the tribunal claim form. Two dates on the process matter enormously for the time limit:

Day A — the day you notified ACAS.
Day B — the day you received the certificate.

How the clock pause actually works

The time limit for most tribunal claims is short — for the common claims, three months less one day from the event. Because conciliation takes time, the law pauses the clock while it happens. Two rules do the work, and they are set out in section 207B of the Employment Rights Act 1996 (with a mirror provision in the Equality Act 2010):

The pause. The period from the day after Day A to Day B doesn't count towards the time limit. In effect, however many days conciliation took are added onto your deadline.
The one-month backstop. If the time limit would otherwise run out between Day A and one month after Day B, it is extended to one month after Day B — so you always have at least a month after the certificate to present the claim, provided ACAS was notified in time.

Where the two rules give different dates, the later one applies.

The single most important point in this guide: the pause only helps if ACAS is notified before the original time limit runs out. Notifying ACAS in time is what protects the claim. A pause cannot rescue a clock that has already stopped — conciliation started after the deadline does not revive it.

The arithmetic has traps — corresponding dates, months of different lengths, and how the two rules interact. Rather than working it out by hand, use the calculator, which applies the statutory rules and shows each step:

Compute your dates →

Common questions

Does early conciliation cost anything? No. It is free.

Do I have to talk to my employer? No — the conciliator speaks to each side separately, and you can decline conciliation entirely and simply obtain the certificate.

Does notifying ACAS commit me to claiming? No. Many people notify ACAS to protect the time limit while they decide. Notification is not a claim.

What if there's more than one employer or respondent? Generally each prospective respondent needs to be named in the notification. This is an area where getting it wrong can cause real problems later — if it applies to you, take advice early.

Are any claims exempt from the requirement? A small number of situations are exempt. They are the exception; assume the requirement applies unless you have confirmed otherwise.

Where to get help with the decision itself

This guide and the calculator can tell you how the process and the dates work. Whether to notify, what your dispute is worth, and whether to settle are questions about your individual situation — for those, ACAS itself (0300 123 1100), your trade union, Citizens Advice, a law centre, or a regulated adviser are the right doors, and the first four are free.

Ready to put this into practice?

The Case Pack (£29) gives you every document a claim needs — the stage-by-stage Tribunal Playbook, a schedule of loss spreadsheet that does the arithmetic, and eight professional templates with guidance at every bracket — launch-priced for the first 100 customers.

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