Set your project value, compensation event frequency and time-bar miss rate below and see the estimated pound value sitting at risk on your project right now, with the maths shown in full.
A missed or time-barred compensation event costs a contractor the full value of that event, permanently. Under NEC4 clause 61.3, if the Contractor does not notify a compensation event within eight weeks of becoming aware of it, the Prices and Completion Date are not changed, unless the event arose from a Project Manager or Supervisor instruction, notification, certificate, or a change to an earlier decision. Entitlement that is not notified in time is not delayed. It is gone.
The estimator below models this at project level: how many compensation events a project like yours is likely to generate, what they are worth, and what share of that value a realistic miss rate puts beyond recovery.Move the sliders to match your project. The figures below update live, and every step of the calculation is shown underneath the headline number so you can check it against your own project rather than take it on faith.
Estimated at-risk value over this project
£43,200
36 compensation events forecast, worth an estimated £288,000, of which roughly 15% is likely to be missed or time-barred
This is not a black box. Total events = CE frequency × programme duration in months. Total CE value = total events × average CE value. At-risk value = total CE value × the time-bar / missed-CE rate you set. These are planning estimates, not a valuation of your actual contract; the demo call is where a QS on our side sanity-checks the assumptions against your real project.
30 minutes. Bring one live contract and we will sanity-check this figure against it.
Take a £10m civils package running 18 months. The commercial team is identifying roughly two clause 60.1 triggers a month, so 36 events over the programme, at an average assessed value of £8,000 once Defined Cost and Fee are applied. That is £288,000 of compensation event value moving through the project.
If 15% of that value is missed, whether because the eight week clock ran out before notification or because the event was never logged at all, £43,200 of entitlement the contractor had already earned is gone by final account. That is not a delay claim or a negotiating position. It is money the contract already owed and the contractor will never collect.
| Input | Value in this example |
|---|---|
| Project value | £10,000,000 |
| Programme duration | 18 months |
| CEs per month | 2 |
| Average CE value | £8,000 |
| Time-bar / missed-CE rate | 15% |
| Estimated at-risk value | £43,200 |
Three patterns show up again and again in site diaries and CE registers. First, the event happens but nobody flags it as a clause 60.1 trigger; a diary entry says "ground harder than expected" and never becomes a physical conditions CE. Second, the event is recognised late; by the time the QS reviews the diary the eight week clock from clause 61.3 has already run. Third, the event is recognised and notified, but the supporting records are thin enough that the quotation gets knocked down in negotiation.
All three failures are record failures, not judgement failures. The team usually knows a CE happened. The gap is between what happened on site and what made it into a register in time.
Gather's AI QS Agent reviews your site diaries against the NEC4 clauses as they are written, flags clause 60.1 triggers your team has not notified yet, and tracks every eight week deadline so nothing runs out the clock unnoticed. In testing it identified 40% more legitimate compensation events than manual review.
See how the AI QS catches missed CEs A 30 minute call. No commitment. Bring one of your live contracts and we will run this estimator against your real numbers.Related reading: the compensation event log template gives you a register to track every CE from notification to implementation, and the 8-week time-bar calculator checks a single event's deadline against clause 61.3.
FAQ
The full assessed value of that event: Defined Cost plus Fee under most NEC4 options, or the equivalent under your contract's valuation rules. If the event is time-barred under clause 61.3, or simply never notified, the Prices and Completion Date are not changed and the entitlement is permanently lost, not delayed to final account.
Total forecast compensation events equals your CE frequency multiplied by the programme duration in months. Total CE value equals total events multiplied by the average CE value. The estimated at-risk value equals total CE value multiplied by your time-bar or missed-CE rate. All three steps are shown live under the headline figure.
It varies by how mature a contractor's CE process is. Teams relying on manual diary review and monthly CE meetings commonly miss more than they realise, which is why Gather's AI QS Agent identifying 40% more legitimate compensation events than manual review is a useful anchor for the scale of the gap. Run the slider at a range of rates to see the sensitivity rather than trusting a single number.
No. This is a planning-level estimate of exposure across a whole project, built to make the scale of the problem visible. An actual CE quotation under clause 62 is built up from Defined Cost first principles for that specific event, not from an average. Use the CE log template to track individual events and their real values.
Gather reads your site diaries as they come in and flags the CEs before the time bar does.
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