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What does LEQ actually mean in acoustics?

LEQ, or Equivalent Continuous Sound Level, is one of the most important metrics in noise measurement and represents the average sound level over a set period.

LEQ, or Equivalent Continuous Sound Level, is one of the most important metrics in noise measurement. It represents the average sound level over a set period, accounting for both the intensity and duration of sound events.

This makes it essential for assessing long-term noise exposure in places like construction sites, industrial environments, and public spaces. Rather than listing constantly changing noise levels, LEQ provides one consistent value that reflects overall exposure. It’s the standard for everything from workplace noise assessments to environmental monitoring.

In this video, we explain exactly what LEQ means, how it’s calculated, and where you’re most likely to encounter it in real-world applications.
Want to explore more acoustic terms and practical guidance? Visit the AcSoft Knowledge Hub — packed with FAQs, technical insights, and expert advice on all things noise and vibration.

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FAQ's

Leq can have two main meanings: as the Equivalent Continuous Sound Level, a measure of average noise energy over time, or as an abbreviation for Less Than or Equal To in computing and mathematics. The sound level meaning is used in noise measurements and environmental standards to represent varying sounds with a single decibel value. The computing meaning is a comparison operator, often written as ≤ is less than or equal to ≤ in mathematics.

Leq is widely used in occupational and environmental noise regulations because it accounts for fluctuating noise over time, providing a single representative value for exposure. Regulatory standards like OSHA, ISO 1996, and EU Directive 2003/10/EC use Leq to evaluate worker safety, community noise limits, and compliance with legal exposure thresholds.

In environments with highly variable or intermittent noise, such as manufacturing plants, construction sites, or airports, Leq provides a time-averaged metric that reflects total acoustic energy exposure. Compliance monitoring often uses Leq with specific averaging periods (e.g., 8-hour work shifts or 24-hour environmental measurements) and may apply frequency weighting (A, C, or Z) and time weighting (Fast or Slow) according to standards like ISO 1996, ISO 9612, and ANSI S1.13.

This approach ensures that noise assessments capture both continuous and impulsive events, producing a single, legally defensible value for exposure limits and environmental impact studies.

Monitoring noise in airports

Stay compliant with accurate LEQ measurement

Leq is widely used in environmental noise regulations because it accounts for fluctuating noise over time, providing a single representative value for exposure. Regulatory standards like OSHA, ISO 1996, and EU Directive 2003/10/EC use Leq to evaluate community noise limits, and compliance with legal exposure thresholds.

Find products to measure environmental noise.

Knowledge

More about LEQ and noise monitoring

What to Expect From a Sound Level Meter

April 18, 2023

Sound level meters are also known as noise meters, decibel meters, or dB meters.  Following BS EN 61672, noise level meters are composed of a microphone, a preamplifier, a signal processor, and a display that displays noise results. Hand-held noise level meters are usually battery-powered and feature a triangular tip and windscreen on top. A sound level meter is a…

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Is There a Difference Between Dynamic Range, Measurement Range and Linearity Range When Looking At Microphones?

January 11, 2023

When I look at the spec sheets for microphones and sound level meters, I see reference to Dynamic Range, Measurement Range and Linearity Range. Surely these are the same, or am I confused? They are completely different definitions, although measurement range and dynamic range are often used interchangeably: Dynamic Range…

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Why am I getting LA,eq values below the LA,90. Surely that’s impossible?

July 12, 2021

No, it’s not impossible at all, and probably it is related to measuring low levels. By having a think about how statistical levels are calculated, all should become clear. Firstly, the LAeq is the A-weighted equivalent energy over a certain period. It’s independent of time weighting (e.g. F), and the…

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Recent and not so Recent Developments in Sound Measurement Instrumentation

June 30, 2019

Introduction The 40th anniversary of the IOA is as good a time as any to review what has happened in the instrumentation market over the same period, and in particular, to the humble sound level meter. This article reviews the basic architecture, and looks at how things have changed, often…

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