exposure · Free · Open Source · MIT

Noise Dose Calculator

Daily noise dose and TWA. Based on OSHA 29 CFR 1910.95 / ACGIH / EU 2003/10/EC. 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

Leq (dB(A))

Exposure hours

Exchange rate

Daily noise dose · OSHA 29 CFR 1910.95

132%

of PEL

8-hour TWA

92 dB(A)

Exchange rate

5 dB

Raw JSON result

{
  "dose": 132,
  "twa8h": 92,
  "actionLevelExceeded": true,
  "permissibleExceeded": true,
  "exchangeRate": 5
}

Overview

About the Noise Dose Calculator

Occupational noise dose under OSHA 29 CFR 1910.95 — the most-cited occupational exposure standard globally. OSHA PEL (Permissible Exposure Limit): 90 dB(A) 8-hour TWA with 5-dB exchange rate. Action level (hearing conservation trigger): 85 dB(A). ACGIH TLV (more conservative) and EU Directive 2003/10/EC use 3-dB exchange rate and an 85 dB(A) limit.

Workers exposed above the action level require audiometric testing, hearing protection provision, and training. Approximately 22 million US workers (NIOSH) have hazardous occupational noise exposure.

Formula

TWA = 90 + Q × log₂(hours / permissible hours)

Regulation

OSHA 29 CFR 1910.95 / ACGIH / EU 2003/10/EC

How to use

Step-by-step: using the Noise Dose Calculator

1
Enter the measured Leq (equivalent continuous sound level in dB(A)).
2
Enter exposure duration in hours.
3
Choose the exchange rate — 5 dB (OSHA) or 3 dB (ACGIH / EU).
4
Read dose %, 8-hour TWA, and action-level status.

Worked examples

Noise Dose Calculator — real-world examples

Concrete mixer operator, OSHA

95 dB(A) for 8 hours with OSHA 5-dB exchange. TWA = 95 dB(A). Dose = 200%. Above PEL — must reduce exposure or provide effective hearing protection + hearing conservation programme.

Who uses this calculator

Used by safety professionals worldwide

●Industrial hygienists running noise surveys
●Manufacturing, construction, mining HSE programs
●Hearing conservation programme coordinators
●Regulator compliance (OSHA, HSE UK, EU member states)

Watch out for

Common mistakes when calculating noise dose calculator

⚠Mixing exchange rates. A value computed with OSHA's 5-dB rate is NOT directly comparable to ACGIH's 3-dB rate.
⚠Reading the sound level meter but not converting to dose. A short exposure to 110 dB(A) is massively more dose than an 8-hour exposure to 85 dB(A).
⚠Assuming hearing protection fully attenuates. Real-world fit reduces rated attenuation by 50% in typical construction use.

FAQ

Frequently asked questions

What is the OSHA noise exposure limit?+

90 dB(A) as 8-hour TWA (PEL). 85 dB(A) TWA is the Action Level triggering hearing conservation programme.

OSHA 5-dB vs ACGIH 3-dB exchange rate?+

OSHA uses 5-dB (every 5 dB halves permissible duration). ACGIH and EU use 3-dB (more conservative, matches equal-energy principle).

Regulation citations

Authoritative sources

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