Free Occupational Safety Calculators
Calculate injury rates, score risks, check noise and heat exposure, and plan your safety training. Every tool shows its formula and a worked example, so you can learn the method as well as get the answer.
Injury Rate Calculators
Calculate TRIFR, LTIFR, incident rate, DART and more. These are the formulas that come up in NEBOSH and OSHA exams and in every company safety report.
- TRIFR CalculatorTotal recordable injuries per 1,000,000 hours
- LTIFR CalculatorLost-time injuries per 1,000,000 hours
- Incident Rate (TRIR) CalculatorOSHA rate per 200,000 hours
- DART Rate CalculatorDays away, restricted or transferred
- Accident Frequency RateAccidents per 100,000 hours worked
- Severity Rate CalculatorDays lost per hours worked
- Lost Time Case RateLost-time cases per 200,000 hours
- Lost Workday RateMeasure productivity lost to injury
- Fatality Rate CalculatorWork-related deaths per 100,000 workers
- Near Miss Frequency RateTrack near misses against hours worked
- Accident Pyramid CalculatorEstimate near misses, minor and major injuries
Risk Assessment Calculators
Score risks with a 5×5 matrix, compare risk before and after controls, and rate your audit results.
- Risk Matrix CalculatorLikelihood x severity with a colour-coded rating
- RPN Calculator (FMEA)Severity x occurrence x detection
- Ergonomic Risk CalculatorAssess strain from posture, force and repetition
- Residual Risk CalculatorCompare risk before and after controls
- Safety Audit Score CalculatorTurn a checklist into a compliance percentage
Health Hazard and Working Conditions
Check noise dose, heat stress and ventilation, and work out safe working limits for height and manual handling.
- Noise Exposure CalculatorDaily dose and 8-hour TWA
- Heat Stress (WBGT) CalculatorWork and rest limits in hot conditions
- Air Changes per HourVentilation rate for a room
- Manual Handling Weight GuideGuideline lifting weights by posture
- Ladder Angle CalculatorSafe placement with the 4:1 rule
- Fall Clearance CalculatorClearance needed below a fall arrest lanyard
Emergency and Compliance Calculators
Work out how many first aiders and fire extinguishers your workplace needs, and how long an evacuation should take.
Safety Management Calculators
Put a number on the cost of accidents, the return on training, and your leading safety indicators.
Student and Career Tools
Built for people starting a safety career: plan your NEBOSH study time, find the right course and split your fee into instalments.
Frequently asked questions
Are these calculators free?
Yes. Every calculator on this page is free to use, with no sign-up.
Which formula should I use: TRIFR, LTIFR or TRIR?
TRIFR counts all recordable injuries per 1,000,000 hours. LTIFR counts only lost-time injuries per the same base. TRIR is the OSHA rate, per 200,000 hours. Pick the one your client, regulator or exam syllabus uses.
Can I use the results in a NEBOSH exam answer?
The formulas match the standard methods taught in NEBOSH and OSHA courses. Always show your working and state the hours base, as examiners expect.
Are the first aider and fire extinguisher results legal advice?
No. They are guidelines based on the standard named on each page. Check the rules that apply in your country and industry.
Turn the formulas into a safety career
ISH Institutes trains students in Peshawar for NEBOSH, OSHA, IOSH, First Aid and Fire Safety. Ask us which course fits your goals.