Calculator · Occupational safety and health

Accident rate calculator and formulas

Enter the accidents, lost days, headcount and hours for the period. The calculator returns the four rates using the formulas of Chile's Supreme Decrees 44 and 67, and below is what each one measures.

Informational guide, not legal advice. Check the current regulation at Ley Chile (Chile's official law library) and consult your safety professional or your mutual insurer (mutualidad).

Accident rate

2.5

accidents per 100 workers · DS 44, art. 73

Lost-day rate

37.5

lost days per 100 workers · DS 67, art. 2

Frequency rate

12.5

injured per million hours · DS 44, art. 73

Severity rate

187.5

lost days per million hours · DS 44, art. 73

What it measures

What the accident rate is

It is the number of injured workers per hundred workers over a period of up to one year (art. 73 of DS 44). With the calculator data, 2.5 out of every hundred: the red dots.

It counts accidents, not days. To see how much they weighed, use the lost-day rate; to compare plants of different size or schedule, use frequency and severity, which are measured per million hours.

The formulas

The four rates, with their formula and article

Accident rate

Formula

Work accidents ÷ workers × 100

Period

Defined period, never longer than one year

Source

DS 44, art. 73 No. 1

Frequency

Formula

Injured × 1,000,000 ÷ hours worked

Period

Monthly

Source

DS 44, art. 73 No. 2

Severity

Formula

(Days absent + charged days) × 1,000,000 ÷ hours worked

Period

Every six months

Source

DS 44, art. 73 No. 3

Temporary disability lost-day rate

Formula

Lost days ÷ average annual headcount × 100

Period

Annual period, July to June

Source

DS 67, art. 2 h)

The calculator does not add charged days to severity: they are added per the ISP charged-days guide when there are permanent disabilities or deaths. DS 67 rounds to two decimals; so does this calculator.

DS 67

Lost-day rate and the additional premium

Annual period 1Jul 1 → Jun 30Annual period 2Jul 1 → Jun 30Annual period 3Jul 1 → Jun 30Evaluation period: average rate of the threeJul 1process

Chile's DS 67 measures the actual accident record to set the differentiated additional premium for workplace accident insurance: exemption, discount or surcharge.

  • · Annual period: July 1 to June 30.
  • · Evaluation period: the three previous annual periods (two if the company has been operating for fewer than three).
  • · Total rate: average temporary disability rate plus the rate for disabilities and deaths.
  • · Process every two years, in odd-numbered years (ISL).

In the app

The rates come from logging every incident

If each incident is logged and signed the day it happens, the monthly count does not depend on anyone remembering.

App screen for logging an incident with a photo, note or voice
Get early accessFree app, in early access.

Frequently asked questions

Accident rate FAQ

How is the accident rate calculated?
Divide the number of work accidents in the period by the total number of workers in the same period and multiply by one hundred. The company defines the period, which cannot exceed one calendar year (art. 73 of DS 44, Chile's Supreme Decree 44).
What is the difference between the accident rate and the lost-day rate?
The accident rate counts accidents per hundred workers. The temporary disability rate under DS 67 (Chile's decree on workplace accident insurance premiums) counts lost days per hundred workers: it measures how long the disabilities lasted, not how many there were.
How are the frequency and severity rates calculated?
Frequency is the number of injured workers per million hours worked; severity is days absent per million hours, adding the charged days set by the ISP (Chile's Public Health Institute) for permanent disabilities and deaths. Injured workers absent for at least one full shift are counted (art. 73 of DS 44).
Which companies must track these rates?
Companies with a Risk Prevention Department track the accident rate, the monthly frequency rate and the six-month severity rate (art. 73). Those not required to have one record, at a minimum, the annual accident rate and every accident (art. 75).
What is the DS 67 lost-day rate used for?
The insurer uses it to assess the company's actual accident record and set the differentiated additional premium: an exemption, a discount or a surcharge. It uses the average of the three annual periods before July 1, plus the rate for disabilities and deaths.
How often is the DS 67 evaluation done?
According to the Instituto de Seguridad Laboral (ISL, Chile's public occupational safety institute), every two years, in the second half of odd-numbered years.

Sources: DS 44, arts. 73 and 75 (BCN) · DS 67, art. 2 (BCN) · SUSESO Compendium, premiums · ISL, DS 67. Reviewed on November 1, 2026.

Keep reading

Occupational health and safety guides

DS 44: the records it requiresThe hub: every preventive-management record, with its article.DS 594 summarizedWorkplace sanitary and environmental conditions, title by title, with their limits.Joint safety committeeDuties, election, job protection and the safety delegate.Risk matrixHow a risk is assessed, with worked plant examples.5-minute safety talksReady-made topics by hazard, plus the attendance record.IRL under DS 44What the occupational risk information must say and when it is delivered.Risk mapWhat the DS 44 risk map includes, with a plant example.Internal safety regulationsWhat the health and safety regulations contain and how they are published.PPE issue logWhat to record when personal protective equipment is handed out.Cause tree analysisAccident investigation step by step, with a worked example.TMERT protocolChecklist, risk levels and deadlines of the MINSAL musculoskeletal protocol.Safe work procedureWhat an SWP is, its sections and a food-plant example.

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