Reverberation Time Calculator

Reverberation time (RT60) is how long sound takes to decay by 60 dB in a room.

How the Math Works

The Reverberation Time Calculator uses the Sabine formula to determine how long it takes for sound to decay by 60 dB in a room. The formula RT60 = 0.161 × V ÷ A requires two key measurements: V (volume in cubic meters) and A (total absorption in sabins). Volume is calculated by multiplying length × width × height, while total absorption sums the absorption coefficients of all surfaces multiplied by their areas. The constant 0.161 accounts for the speed of sound and air's absorption properties, giving the time in seconds for sound to drop 60 decibels.

Practical Applications

To use this calculator practically, first measure your room's dimensions and calculate the volume. Then identify the surface materials - concrete, carpet, drywall, etc. - and find their absorption coefficients from acoustic reference tables. Multiply each surface's area by its coefficient to get sabins, then sum all surfaces for total absorption A. Input these values into the formula or calculator to determine RT60. For example, a room with 200 m³ volume and 150 sabins of absorption has an RT60 of 0.215 seconds.

Day-to-Day Use

Knowing your room's reverberation time helps create acoustically comfortable spaces for music practice, podcast recording, or movie watching. Short RT60 values (under 0.3 seconds) create dry, clear sound ideal for speech, while longer RT60 values (1-2 seconds) produce warm, rich reverberation perfect for concert halls. You can use this calculation to choose appropriate acoustic treatments like acoustic panels, bass traps, or even furniture placement to achieve your desired sound quality without expensive professional acoustic analysis.

Worked example

200 m³ room with 30 sabins → about 1.07 s.

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