Total exposure hours. Based on OSHA / ISO 45001 reporting convention. 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.
{
"regular": 33000,
"overtime": 4950,
"total": 37950,
"exposureHours": 37950
}Total manhours (exposure hours) is the denominator in almost every HSE rate calculation — TRIR, LTIR, LTIFR, DART, severity, frequency. Incorrect manhours under-reports or over-reports rates by proportional error. This calculator handles regular + overtime across arbitrary shift patterns.
Under OSHA 29 CFR 1904.7, hours worked for rate calculation means actual on-the-clock hours — vacation, sick leave, bereavement, holiday-off-duty do NOT count. Overtime counts whether paid at a premium rate or not.
Total = Workers × Hours/Day × Days × (1 + Overtime %)OSHA / ISO 45001 reporting convention
150 workers × 10 hours/day × 20 days × 1.15 (15% OT) = 34,500 hours. Use this as the denominator for the month's TRIR.
Yes — all hours actually worked count, regardless of pay rate.
Free for any website, blog, or course — MIT / CC BY 4.0. Attribution stays visible.
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