Reverberation time (T, s), a concept introduced by W.C. Sabine at the end of 19th century, remains one of the most important acoustic properties of the room. Standard reverberation time is defined as that time required for the sound-pressure level in a room to decay 60 dB after a source stops generating sound. It characterizes degree of boominess of the room.


In general, shortening of reverberation time leads to better clarity and speech articulation, i.e. increases the degree of acoustic comfort. Shortening of reverberation time is achieved by using sound absorbing materials on the walls, floor, and ceiling.


This acoustic calculator is meant to estimate reverberation time of the room depending on its purpose, and to preselect required quantity of sound absorbing materials. Besides using internal database of sound absorbing materials, the program allows to enter sound absorption coefficients of any arbitrary materials taken from reference books (Sound absorption coefficients table).


Calculations with Reverberation time RT60 calculator are based on online input. Results are displayed on a diagram. Calculation is performed in accordance with Eyring's formula:


Т (sec) = 0,163*V / (−ln(1−α)*S + 4*µ*V) 

V – volume of the room, m3
S – total surface area of the room, m2
α - average absorption coefficient of room surfaces
µ - a coefficient which takes account of attenuation of sound in air


Calculated value of reverberation time is graphically compared to recommended (optimum) values are in compliance with international standards:


DIN 18041 Acoustic quality in rooms-Specifications and instructions for the room acoustic design, 2016

EBU Tech. 3276 – Listening conditions for sound programme, 2004

IEC 60268-13 (2nd edition) Sound system equipment - Part 13, 1998


Please read our rights of use