NEBOSH International Diploma for Occupational Health and Safety Management Professionals — Free Online Mock Test
NEBOSH International Diploma knowledge checks across all three units: DI1 Know — workplace health and safety principles, DI2 Do — controlling workplace health issues, and DI3 Do — controlling workplace safety issues. The real Diploma (RQF Level 6) is assessed by a DI1 assignment and DI2/DI3 case studies with closing interviews, 50% per unit; these mocks drill the Diploma-depth knowledge those assessments demand. · Official language: English.
NEBOSH International Diploma exam at a glance
NEBOSH International Diploma full-length mock tests
Attempt 50 full-length NEBOSH International Diploma mock tests, each a distinct question set built on the real 60-question, 90-minute pattern — with instant scoring and section-wise analysis. The first 3 are free.
NEBOSH International Diploma key facts & eligibility
| Conducting body | NEBOSH (The National Examination Board in Occupational Safety and Health), UK — taught through NEBOSH-accredited Learning Partners worldwide |
|---|---|
| Official website | nebosh.org.uk ↗ |
| Mode | Three units, all completed remotely and submitted online. DI1 (Know – workplace health and safety principles) is an assignment of about 40 hours split over two papers taken at the same sitting: Paper 1 is simulation questions and Paper 2 is workplace activities, reflective tasks and a research project based on a real organisation. DI2 (controlling workplace health issues) and DI3 (controlling workplace safety issues) are scenario-based case studies of about 20 hours each. NEBOSH allows four weeks to submit DI1 and two weeks each for DI2 and DI3. Every submission is checked with plagiarism software and followed by a closing interview about your work. |
| Frequency | Each unit has two NEBOSH-set assessment windows a year. In 2026, DI1 ran in March and September, DI2 in May and November, and DI3 in January and July. Learning Partners may teach the units in any order and run courses year-round as block-release, part-time, distance and e-learning programmes. |
| Scoring & marking | Each unit has a provisional pass mark of 50%. The percentage marks of all three units are added together to set the qualification grade: Distinction 226 or more, Credit 196–225, Pass 150–195 and Refer 0–149. You must pass all three units, and if you re-sit a unit, your highest mark counts. |
| Score validity | You have a five-year enrolment period to pass all three units, counted from your enrolment date or the declaration date of your first successful unit, whichever is later. Re-sits are unlimited within that period, though each one costs extra. The parchment is normally issued about 20 working days after the result of your third successful unit, and holders may use the letters IDipNEBOSH. |
| Language | English only — the assessments are currently offered, and must be answered, in English. |
Who is eligible for NEBOSH International Diploma?
There are no formal entry requirements, but the syllabus assumes the knowledge of the NEBOSH International General Certificate. NEBOSH strongly recommends passing the IGC or an equivalent RQF Level 3 or 4 qualification first, and an English level equivalent to IELTS 7.0 or higher.
Last verified October 2026 against NEBOSH — International Diploma qualification page, NEBOSH — International Diploma qualification guide for Learning Partners (v2, June 2025), NEBOSH — International Diploma leaflet, NEBOSH — previous International Diploma (IA/IB/IC/DNI), withdrawn. Always confirm current details on the official website before you register.
NEBOSH International Diploma section breakdown
The NEBOSH International Diploma mock test on Wrexa Edge replicates the real exam's section structure — same names, same question count per section, same time limits. No inter-section breaks — the timer runs continuously.
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DI1–DI3 Knowledge Check (60 Q)
NEBOSH International Diploma scoring & marking scheme
Strategy: NEBOSH International Diploma has no negative marking. Attempt every question — blank answers cost you potential marks but cannot pull your score down.
Scale: NEBOSH Diploma knowledge (%).
How NEBOSH International Diploma is conducted
- Mode
- Test format
- Backtracking
- Mark for review
NEBOSH International Diploma time strategy
With 60 questions in 90 minutes, you have about 90 seconds per question on average. Successful candidates aim for the following pacing on each section:
- DI1–DI3 Knowledge Check (60 Q)
Wrexa Edge's analytics show your actual time-per-question after every mock so you can spot which sections you're losing time on.
NEBOSH International Diploma topics covered
Across the 50 Wrexa Edge variants of NEBOSH International Diploma, the following topics appear most often (sample distribution from one variant):
DI1–DI3 Knowledge Check (60 Q)
- NEBOSH Diploma — DI1: Loss causation and quantitative analysis of data · 4
- NEBOSH Diploma — DI1: Legislation, enforcement, ILO and non-governmental bodies · 4
- NEBOSH Diploma — DI1: Health and safety culture and proactive safety management · 3
- NEBOSH Diploma — DI2: Hazardous substances, classification and toxicology · 3
- NEBOSH Diploma — DI3: Fire and explosion mechanisms and protection · 3
- NEBOSH Diploma — DI3: Electricity · 2
- NEBOSH Diploma — DI1: Societal factors, CSR and organisational change · 2
- NEBOSH Diploma — DI2: Asbestos and lead · 2
NEBOSH International Diploma difficulty calibration
Elite tier. Elite-tier: among the toughest exams in its category. Most successful candidates prepare for 6-12+ months.
NEBOSH International Diploma knowledge checks across all three units: DI1 Know — workplace health and safety principles, DI2 Do — controlling workplace health issues, and DI3 Do — controlling workplace safety issues. The real Diploma (RQF Level 6) is assessed by a DI1 assignment and DI2/DI3 case studies with closing interviews, 50% per unit; these mocks drill the Diploma-depth knowledge those assessments demand. · Official language: English.
Verified content — Wrexa Edge's NEBOSH International Diploma bank has been deeply curated with real exam-aligned content (estimated 65% syllabus coverage).
How Wrexa Edge prepares you for NEBOSH International Diploma
- Real test-day interface
- 50 distinct variants
- Detailed analytics
- Spaced repetition (Notebook)
- Optional proctoring
- Free to start
Expert take: what NEBOSH International Diploma really tests
The NEBOSH International Diploma (May 2023 specification) is a Level 6 qualification with three units, all assessed remotely and none by multiple-choice exam. DI1 is a roughly 40-hour assignment made of simulation questions plus workplace activities, reflective tasks and a research project. DI2 and DI3 are roughly 20-hour case studies on health and safety issues. Every submission ends with a closing interview. Each unit needs a provisional 50%, and the three percentages are added together: 226+ earns a Distinction, 196–225 a Credit and 150–195 a Pass. The syllabus assumes IGC-level knowledge and uses international frameworks (ILO conventions, ISO 45001, ISO 12100, GHS), along with British HSE guidance where the syllabus names it.
Preparation tips
- Treat the IGC as assumed knowledge — the Diploma leaves out content already covered there, so revise the "Prior learning" table before you start.
- In case studies, apply theory to the scenario: name the model (e.g., Reason, HSG48, bowtie) and then show exactly how it explains the facts given.
- Practise the numbers until they are automatic — TWA, A(8) and vibration points, dB addition, incidence and frequency rates, payback periods.
- Choose a DI1 Paper 2 workplace with enough scope early; it does not have to be your employer.
- Prepare for each closing interview by being able to explain, in your own words, why you reached each recommendation.
Common mistakes to avoid
- Writing generic textbook answers that ignore the scenario — marks go to applied, organisation-specific reasoning.
- Leaving DI1 too late: it is the longest assessment and has the widest syllabus, covering eight learning outcomes.
- Relying on UK-only law. The International Diploma is framed around ILO conventions and international standards, with HSE documents used as named guidance.
- Forgetting the five-year enrolment limit when spacing out units and re-sits.
NEBOSH International Diploma study plan
A phase-by-phase roadmap from your first concept to test-ready. Stretch or compress each phase to fit the time you have before your attempt.
- Check your IGC-level prior learning against the "Prior learning" table in the qualification guide and fill any gaps
- Goal-setting vs prescriptive law, HSE41 enforcement principles, ILO C155/R164 and C187, and the role of NGOs and insurers
- Leadership styles, HSG263 consultation, culture and climate, Safety-II/HOP, risk perception and HSG48 human failure
- HAZOP, FMEA, fault and event trees, bowtie, 5-Whys and fishbone; Reason's model; incident rate calculations
- Leading and lagging indicators, audits, sampling and surveys, benchmarking, and the inputs and outputs of performance reviews
- Cost-benefit and payback arguments, ethics, CSR, managing change with the Kubler-Ross curve, and contractor and supply-chain control
- Start the DI1 Paper 2 workplace activities and the research project on your chosen organisation
- Occupational health services, rehabilitation, mental ill-health and the HSE Management Standards, violence and lone working
- Toxicology, epidemiology, GHS/CLP, exposure limits and TWA calculations, monitoring strategy, LEV and RPE selection
- Noise (dB arithmetic, hearing protector selection), vibration (A(8) and points), radiation, musculoskeletal tools (MAC, ART, V-MAC), thermal stress
- Fire and explosion science, zoning and Ex equipment, dust explosions, fire risk assessment and means of escape
- Maintenance strategies, failure modes and NDT, ISO 12100 machinery safety, mobile and lifting equipment, electricity, construction and transport
- Work through full case studies against the clock, then rehearse explaining your reasoning for the closing interview
Where NEBOSH International Diploma can take you
A strong NEBOSH International Diploma result opens up these careers and higher-study paths:
- Health and safety manager / HSE manager
- HSE adviser or consultant
- Regional or corporate HSE lead
- Route to professional membership
- Postgraduate study
Best books & official prep for NEBOSH International Diploma
- NEBOSH International Diploma qualification guide (May 2023 specification) — NEBOSH
- ISO 45001 — Occupational health and safety management systems — International Organization for Standardization
- Reducing error and influencing behaviour (HSG48) — Health and Safety Executive (UK)
- Safety-I and Safety-II: The Past and Future of Safety Management — Erik Hollnagel
- Just Culture — Sidney Dekker
Official practice: Download the qualification guide and the qualification resources (tutor references, leaflet and case studies) from nebosh.org.uk. For DI1 Paper 2, choose a suitable workplace early. It does not have to be your own, but it must give enough scope for the workplace activities. NEBOSH recommends a programme of at least 185 taught hours plus about 144 hours of self-study, with roughly 80 further hours for the assessments.
Previous-year papers: NEBOSH does not publish completed past assessments to reuse. Each DI1 assignment and DI2/DI3 case study is a fresh scenario, and plagiarism checks and closing interviews mean rehearsed answers will not help. Practise by applying the syllabus to case studies from your Learning Partner and to NEBOSH's own published case-study resources.
Sample NEBOSH International Diploma practice questions
5 questions taken from the NEBOSH International Diploma mock tests on Wrexa Edge. Try each one, then reveal the answer.
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Q1. Most faults on portable electrical equipment are found by?
- Insulation resistance instrument tests only
- Visual checks
- Thermal imaging surveys of each appliance
- An annual external management system audit
Show answer
Answer: B — Visual checks
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Q2. When a restructure removes a role, which action BEST protects safety?
- Assume the remaining staff will pick up the tasks informally
- Delete those tasks from all procedures and instructions
- Explicitly reassign its safety-critical tasks
- Wait for an incident to reveal gaps
Show answer
Answer: C — Explicitly reassign its safety-critical tasks
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Q3. When testing a confined space atmosphere with a multi-gas detector, what is normally tested FIRST?
- Toxic gases
- Flammable gases
- Air temperature
- Oxygen
Show answer
Answer: D — Oxygen
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Q4. Which is one of the five key principles of Human and Organisational Performance (HOP)?
- Context drives behaviour
- Zero human error is achievable
- Discipline reliably prevents recurrence
- Procedures remove all variability
Show answer
Answer: A — Context drives behaviour
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Q5. Which type of asbestos is a serpentine fibre, often called "white asbestos"?
- Crocidolite
- Chrysotile
- Amosite
- Tremolite
Show answer
Answer: B — Chrysotile
Frequently asked questions
- What are the units of the NEBOSH International Diploma?
- The current (May 2023 specification) Diploma has three units. DI1 is "Know – workplace health and safety principles", DI2 is "Do – controlling workplace health issues" and DI3 is "Do – controlling workplace safety issues", all marked (International). They replaced the older IA, IB, IC and DNI units, which have been withdrawn.
- How is the NEBOSH International Diploma assessed?
- DI1 is an assignment of about 40 hours in two papers: Paper 1 is simulation questions, and Paper 2 is workplace activities, reflective tasks and a research project. DI2 and DI3 are scenario-based case studies of about 20 hours each. You get four weeks to submit DI1 and two weeks each for DI2 and DI3, and every assessment is followed by a closing interview.
- What is the pass mark and grading for the NEBOSH Diploma?
- Each unit has a provisional pass mark of 50%. Your three unit percentages are added together: 226 or more is a Distinction, 196–225 a Credit, 150–195 a Pass and 149 or below a Refer. If you re-sit a unit, your highest mark counts.
- Does the NEBOSH Diploma have multiple-choice questions?
- No. All three units are written assignments or case studies followed by a closing interview. Wrexa Edge uses multiple-choice questions as a fast knowledge check across the DI1, DI2 and DI3 syllabus — the theory you must then apply in the written assessments.
- Do I need the NEBOSH IGC before the International Diploma?
- There are no formal entry requirements. However, the Diploma syllabus assumes IGC-level knowledge and leaves out content the IGC already covers, so NEBOSH strongly recommends passing the IGC or an equivalent RQF Level 3 or 4 qualification first. NEBOSH also recommends English at IELTS 7.0 or higher.
- How long do I have to complete the NEBOSH International Diploma?
- You have a five-year enrolment period to pass all three units. It starts from your enrolment date or the declaration date of your first successful unit, whichever is later. NEBOSH recommends at least 185 taught hours plus about 144 hours of self-study.
- In which language can I take the NEBOSH International Diploma?
- English only. The assessments are currently offered, and must be answered, in English, which is why NEBOSH recommends an English level of about IELTS 7.0.
- Does the NEBOSH Diploma make me a Chartered member of IOSH?
- Not by itself. The Diploma meets the academic requirements to apply for IOSH membership at the appropriate grade. Chartered status (CMIOSH) then needs further professional development assessed by IOSH. Holders can also use the letters IDipNEBOSH.
- How can I practise NEBOSH International Diploma online for free?
- Wrexa Edge gives you 3 free full-length NEBOSH International Diploma mock tests — with instant scoring, detailed explanations and analytics — plus 47 more with Pro. Start practising in under a minute, no card required.
- Can I take the NEBOSH International Diploma mock test on mobile?
- Yes. NEBOSH International Diploma mock tests run in any browser on mobile, tablet or desktop — no app or download needed. Start on your phone and your progress and analytics sync when you sign in.
- What is the eligibility for NEBOSH International Diploma?
- There are no formal entry requirements, but the syllabus assumes the knowledge of the NEBOSH International General Certificate. NEBOSH strongly recommends passing the IGC or an equivalent RQF Level 3 or 4 qualification first, and an English level equivalent to IELTS 7.0 or higher. Wrexa Edge focuses on realistic NEBOSH International Diploma practice: 3 free full-length mocks in the exact exam pattern, ready whenever you are.
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