Reverberation Time Calculator

Written by Great Medico

Updated September 25, 2026 •2 min read

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The quickest way to trust a reverberation time estimate is to see how the answer responds when an input changes. Acoustic quantities mix linear measurements with logarithmic levels, material properties, and wave relationships, so the meaning of each input matters as much as the arithmetic. The sections below show what this page calculates, how it does it, and where the simplified model stops.

What this calculator does

This calculator isolates the relationship between Room length, Room width, Room height and reverberation time. That makes it easier to see which input is controlling the result and to distinguish the headline quantity from secondary values shown underneath.

How to use it

For a clean calculation, enter Room length, Room width, Room height, Door height, Door width exactly as defined by the labels and their units. Check the headline value, then scan the supporting metrics for a relationship that should obviously increase or decrease with one input; this is a fast way to catch an entry mistake.

How the calculation works

The page uses a Sabine-style estimate RT60 = 0.161V/Aeff. Room volume is V = length×width×height, while Aeff is the single absorption coefficient multiplied by room surface area after the entered door and window openings are subtracted.

Example

Using the default example on the page (Room length = 5 m; Room width = 4 m; Room height = 3 m; Door height = 2 m), the calculator returns reverberation time of 0.540752 s. If a small input change sends the value in the opposite direction from the equation, recheck the selected unit and sign convention.

How to interpret the result

Interpret the reverberation time in the acoustic context shown on the page. If the result is in decibels, remember that it is logarithmic; if it is a frequency, wavelength, speed, or coefficient, keep the stated medium and reference quantities attached to the comparison.

Limitations and notes

This is a single-coefficient Sabine-style estimate. It does not assign separate absorption to each wall, floor, ceiling, furnishing, door, or window, and it does not test whether the room is sufficiently diffuse for Sabine’s assumptions. Frequency-dependent RT60 can differ substantially.