CDM 2015
Notification Calculator

cdm 2015 Notification Calculator

Use our free CDM 2015 notification calculator to check if your construction project needs to be notified.

Under CDM 2015, notification requirements apply to all construction projects. If your project reaches the notification threshold, regardless of whether the project is classed as domestic or commercial, it will require notification to the HSE.

Important: All CDM duties including the need to appoint the principal designer and principal contractor roles apply even if the project is not notifiable.

Is your project notifiable?

To find out if your project needs to be notified under CDM 2015, enter the project duration in days (each part day worked counts as a day) and the number of people you expect to have on site.

If the number of person days exceeds 500 then the project is notifiable under CDM 2015 (or where you have over 20 workers on your project at any one time and the project lasts over 30 days).

Person days
Enter your project details
Remember! All CDM duties apply even if your project is not notifiable.


The basics of notification under CDM 2015

If your project will ever have more than 20 workers, at any one time, and the project exceeds 30 working days (including part days) - it is notifiable.

It is also important to check on the person days, because a project can still become notifiable under 30 days with less than 20 people. For example, a project lasting 29 days with 19 workers would still require notification because it exceeds the 500 person day rule.

The notification thresholds are where the project will:

  1. Last longer than 30 working days and have more than 20 workers working simultaneously at any point in the project, or
  2. Exceed 500 person days
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Are you a CDM duty holder? Read our free CDM guides.