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How Is the NEBOSH Diploma Assessed? | Assessment Breakdown & Pass Marks

January 2026


The NEBOSH Level 6 Diploma for Occupational Health and Safety Professionals is the gold standard of health and safety qualifications. Those who successfully complete the course are acknowledged by their peers as being in the upper echelon of expertise in the field. With this in mind, it should be no surprise that the assessments are well known for their challenge.

For the NEBOSH Diploma to remain the most prominent health and safety training qualification, the course must be regularly updated to educate learners on effective workplace health and safety. The course must also consider health, safety and environmental regulations and cover the latest compliance guidelines.


What Are the NEBOSH Diploma Assessments?

The assessments for each 'Unit' of the NEBOSH Diploma are as follows:

  • Unit DN/1DI1: An 8,000-word report that reviews health and safety management arrangements and proposes improvements. This assignment should be based on a real workplace, so learners can elect to use their workplace or a suitable alternative.
  • Unit DN2/DI2: A scenario-based case study assessment requiring you to analyse a workplace situation and apply your knowledge to identify and control health risks. The DN2 assessment requires you to apply the health and safety knowledge gained in the course to practical situations.
  • Unit DN3/DI3: Another scenario-based case study assessment, based on a real-world situation.

Pass Marks

Since the May 2023 specification, all three NEBOSH Level 6 Diploma assessments have had a total of 650 marks up for grabs.

  • DN1/DI1: 300 total marks - 50% or higher needed to pass.
  • DN2/ID2: 175 total marks - 50% or higher needed to pass.
  • DN3/DI3: 175 total marks - 50% or higher needed to pass.

DN1/DI1 consists of two papers, but the second paper will have one combined part, grouping parts 2, 3 and 4. Paper one will consist of 100 marks, and paper two is 200 marks.

Paper one is a scenario-based assessment, asking how learners would act and behave in a real-world situation. Paper two holds the rest of the assignment activities, which include:

  • Workplace activities.
  • Reflective tasks.
  • Research project.

Assessment Durations

Each of the NEBOSH Level 6 Diploma assessments takes a considerable chunk of time to complete, broken down into the following sections:

  • DN1/DI1 Assessment: 40 hours completion time. The submission window is reduced from the assessment release date, formerly a six-week window, now a four-week window.
  • DN2/DI2 Case Study Assessment: 20 hours completion time. The submission window will reduce from four weeks to two weeks. 
  • DN3/DI3 - Case Study Assessment: 20 hours completion time. The submission window is reduced from four weeks to two weeks from the assessment release date.

In order to pass these comprehensive assessments, you'll need to ensure you have some level of foundational knowledge about health and safety, gained through the NEBOSH General Certificate. Although not a formal entry requirement, it's highly recommended in order to give you the best chance at success.


Why Were the NEBOSH Diploma Assessment Times Reduced in May 2023?

NEBOSH has reduced assessment hours to save learners time. The assessments will remain the same, but NEBOSH claims learners do not need the specified time in the previous specification. Instead, a reduced timeframe will allow learners to flow through the course at a better pace without reducing the course content and learning outcomes. 

Once learners achieve a pass in each of their unit assessments, the qualification is complete. Then it's time for grading. The grading is calculated by adding the combined percentage mark for all three units. After that, the following grading boundaries are applied:

  • Distinction: 226% or higher
  • Credit: 196-225%
  • Pass: 150-195%

To pass the NEBOSH Level 6 Diploma, learners must achieve at least 50% of each unit's marks. NEBOSH will add each of the percentage marks (50% x3) to get to 150%.

How Long Does the NEBOSH Level 6 Diploma Take to Complete?

NEBOSH insist that the current specification of the NEBOSH Level 6 Diploma should take approximately 415 hours.

UnitTaught HoursSelf-Study HoursAssessment HoursTotal HoursCredits
DN177584017518
DN260452012513
DN354412011512
Total1911448041543

For more information on the duration of the NEBOSH Level 6 Diploma, we have broken down the amount of time needed to complete of the course. 

For more information and analysis on the course syllabus, you can head over to the National or International course pages below to view our syllabus guide, frequently asked questions, and even try a free online course demo.




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