Why the decibel is currently missing from the world's standard

Music · Published 18 October 2026 Swipe more like this →

In short: The decibel is the universal language of sound, yet it currently lacks a formal definition in the primary international standard for quantities and units. This technical oversight creates a strange vacuum in the global style guide for scientific and educational documents regarding acoustics.

The ISO/IEC 80000 series serves as the definitive international style guide for physical quantities, units, and mathematical formulas. To guarantee a uniform measurement framework for global teachers and researchers, this standard was created through a partnership between the International Electrotechnical Commission (IEC) and the International Organization for Standardization (ISO). While it covers vast fields—from thermodynamics and mechanics to electromagnetism and information technology—it faces a unique structural challenge regarding acoustics.

In 2019, a revision of ISO 80000-3 (quantities of space and time) led to the omission of the decibel definition from the 2006 publication. This left the standard without a formal definition for one of the most common units in human experience. To address this gap, a new specific part of the standard, IEC 80000-15, which focuses on logarithmic and related quantities, is currently under development.

Despite this specific omission, the broader ISO 80000-8:2020 standard remains the primary authority for acoustics. It provides the necessary framework for sound pressure, sound power, and sound exposure levels. It also defines critical technical parameters like characteristic impedance for longitudinal waves, ensuring that while the decibel's specific definition is being relocated, the physics of sound remains standardized.

This highlights the complexity of international standardization. As technology evolves, standards must be partitioned into more specific categories—like the move toward IEC 80000-13 for information technology—to maintain precision across different disciplines.

General information, not professional advice. Spotted an error? Flag the card or see corrections and complaints.

Intellect Plus is a visual educational discovery platform for exploring fascinating facts and ideas. Brain Food, Not Brain Rot. What is Intellect Plus?

Related

• Two tones with equal sound pressure can sound unequally loud. Blame your ears.
• The decibel began as a way of measuring miles of telephone cable
• Why the decibel scale makes a whisper feel like a roar in reverse
• Why engineers prefer the neper over the decibel for measuring signal changes
• Why your ears hear a roar but your meter sees a whisper
• Is your data accurate, or is the measurement process itself broken?
• Why 'five nines' of availability is harder than it sounds
• Why no measurement is ever truly exact
• How scientists see the invisible dance of moving fluids
• The invisible line where noise ends and reality begins
• Is a number actually a quantity, or just a ghost of one?
• How scientists use light to weigh the invisible contents of a solution

More in Measurement · More in Music · Latest · A–Z · All topics