incident rates · Free · Open Source · MIT

Frequency Rate Calculator

International accident frequency rate. Based on HSE UK / IOGP. Results shown with the full formula so you can verify. Zero signup, zero tracking, zero data sent to a server — all calculation is client-side.

Inputs
Frequency Rate Calculator result
2.5
per 1,000,000 hours
(5 × 1,000,000) ÷ 2,000,000
Equivalent LTIFR (1M base)
2.50
ISO 45001 / ILO international standard
Equivalent OSHA (200k base)
0.50
OSHA 29 CFR 1904.7 US standard
Raw JSON result
{
  "rate": 2.5,
  "base": 1000000,
  "formula": "(5 × 1,000,000) ÷ 2,000,000"
}
Overview

About the Frequency Rate Calculator

International Accident Frequency Rate (AFR) — HSE UK / IOGP standard. 1,000,000-hour base. Used by UK and most Commonwealth countries for mandatory reporting, and by IOGP members for global oil & gas benchmarking.

Convertible to OSHA TRIR via the 5× rule of thumb (TRIR ≈ AFR ÷ 5 approximately, though scope differs).

Formula
AFR = (Reportable Accidents × 1,000,000) ÷ Hours Worked
Regulation

HSE UK / IOGP

How to use

Step-by-step: using the Frequency Rate Calculator

  1. 1
    Count accidents. Enter hours. Read AFR.
Who uses this calculator

Used by safety professionals worldwide

FAQ

Frequently asked questions

AFR vs TRIR?+

Different bases — 1M (AFR) vs 200k (TRIR). Different scopes — AFR varies by regulator; TRIR is OSHA-defined.

Regulation citations

Authoritative sources

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Free for any website, blog, or course — MIT / CC BY 4.0. Attribution stays visible.

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Optional attributes: data-theme, data-width, data-min-height. Works on any CMS (WordPress, Webflow, Ghost, plain HTML).
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