Compensation Event Timeline Calculator
By Sheldon Wright MCICES. Last reviewed September 2026. Covers the NEC3 and NEC4 ECC and ECS.
Most compensation event arguments about time come down to somebody counting the weeks wrongly, or not counting them at all. Enter the dates you know, and the calculator shows each date that follows under the standard form.
Enter a date above and the timeline appears here.
Dates are the easy part.
Clause 60 reviews the content of a compensation event: the notification, the quotation, the programme and the records, against your contract including its Z clauses. Every finding is cited to its source document. See a full sample review, no sign-up needed.
Or take the dates with you: the free NEC templates include registers that calculate every one of these deadlines in Excel.
How the compensation event timeline works
The periods below are the standard ones in the main contract. The subcontract periods are different, and the calculator handles those too.
| Step | Who | Standard period (NEC3 and NEC4 ECC) |
|---|---|---|
| Notify an event the Contractor believes is a compensation event | Contractor | Eight weeks from becoming aware of it |
| Reply to the notification, and instruct quotations if it is a compensation event | Project Manager | One week, or longer if the Contractor agrees |
| If there is no reply, remind the Project Manager | Contractor | No fixed period, but nothing further happens until this is done |
| Notification treated as accepted if there is still no reply | Two weeks after the reminder | |
| Submit the quotation | Contractor | Three weeks from the instruction |
| Reply to the quotation | Project Manager | Two weeks from submission |
| Submit a revised quotation, if instructed | Contractor | Three weeks from that instruction |
| If there is no reply to the quotation, remind the Project Manager | Contractor | No fixed period |
| Quotation treated as accepted if there is still no reply | Two weeks after the reminder | |
| Project Manager’s own assessment, where the contract allows one | Project Manager | The same period the Contractor had for the quotation, from when the need for it became apparent |
Run end to end with every period used in full and no reminders, a Contractor-notified event takes six weeks from notification to the Project Manager’s reply on the quotation. If the Project Manager misses both replies and the Contractor reminds promptly each time, it takes about ten.
Four things the dates will not tell you
Whether the eight weeks has started. The period runs from when the Contractor became aware of the event. That is a question of fact and it is often the real argument.
Whether the time bar applies to your event at all. The standard form lifts it for some events that come from the Project Manager’s or Supervisor’s own actions. The wording of that exception differs between NEC3 and NEC4, and between editions of NEC3.
Whether silence means acceptance. It does not, until the Contractor has sent the reminder and a further two weeks have passed. Many Contractors skip the reminder and assume the quotation has gone through.
Whether your contract has changed any of this. Z clauses commonly shorten the notification period, lengthen the Project Manager’s reply periods, or delete the treated acceptance provisions altogether. The calculator works from the standard form. Always check the dates against your own contract.
Subcontracts
Under the NEC subcontract the Subcontractor has seven weeks to notify, one week less than the main contract, so that the Contractor has time to pass the event up the line. The reply periods are longer for the same reason. The quotation period is one week under the NEC3 subcontract and two weeks under NEC4. Subcontractors are regularly caught by these shorter periods because they assume the main contract periods apply.
Frequently asked questions
How long does a Contractor have to notify a compensation event?
Eight weeks from becoming aware of the event under the NEC3 and NEC4 main contracts, and seven weeks under the subcontracts, unless the contract has been amended.
How long does the Project Manager have to respond to a compensation event notification?
One week under the standard main contract, or a longer period if the Contractor agrees to one.
How long does the Contractor have to submit a compensation event quotation?
Three weeks from being instructed to submit it. The period can be extended by agreement before it runs out.
What if the Project Manager has not replied to my quotation after two weeks?
Nothing, until the Contractor notifies the Project Manager of the failure. If there is still no reply two weeks after that notice, the standard form treats the quotation as accepted.
Do weekends and bank holidays count?
Yes. The periods are in weeks and the standard form makes no allowance for holidays.
Does the calculator store my dates?
No. The calculation runs in your browser and nothing you enter is sent to us.
This calculator and page give general guidance on the standard NEC3 and NEC4 forms. They are not legal advice, and they do not account for the amendments in your contract. NEC is a registered trade mark of its owner; Clause 60 Limited is not affiliated with or endorsed by NEC.