Assumes a single, constant noise level for the full duration entered (the “equal energy” model used by OSHA, NIOSH and the EU Noise Directive). Real workdays usually involve varying levels — for mixed exposures, calculate the dose for each task and add the percentages together. OSHA uses a 90 dB(A) / 5 dB exchange rate; NIOSH and the EU Noise Directive use an 85 dB(A) / 3 dB exchange rate. The EU directive’s upper action value (85 dB(A)) and limit value (87 dB(A), with hearing protection) are noted for reference. This tool is for general reference only and is not a substitute for a calibrated dosimeter or a professional industrial hygiene assessment.
The phon scale is defined so that, for a 1 kHz pure tone, phon equals dB SPL — this calculator uses that reference point directly, so it is most accurate for tones near 1 kHz and only approximate for complex or low/high‑frequency sounds (a full conversion needs the ISO 226 equal‑loudness contours). Sone follows Stevens’ loudness relation, where each doubling of sone represents a roughly twice‑as‑loud sound to the average listener, with 1 sone defined as 40 phon.
Check whether a noise level is safe for the time you're exposed to it. This free calculator compares your daily noise dose against OSHA, NIOSH, and EU Noise Directive limits side by side, so you can see at a glance whether hearing protection is recommended — or required. It also includes a quick dB to phon to sone converter for translating sound pressure level into perceived loudness.