Room Absorption (Sabine) Calculator
Work out the total sound absorption of a room in metric sabins from its surface area and average absorption coefficient — and, if you know the room volume, estimate the Sabine reverberation time (RT60).
Enter Values
How to use this calculator
- Enter the total interior surface area in square metres and the average absorption coefficient (0 to 1).
- Optionally enter the room volume in cubic metres to also get the RT60 reverberation time.
- Read the total absorption in metric sabins and the estimated RT60 in seconds.
How it works
Total absorption A is the surface area multiplied by the average absorption coefficient, expressed in metric sabins (one sabin equals one square metre of perfect absorber). Sabine's formula then estimates reverberation time as RT60 = 0.161 × V ÷ A, where V is the room volume in cubic metres and 0.161 is the metric constant. RT60 is the time for sound to decay by 60 dB after the source stops.
Worked example
Worked example. A room with 100 m² of surface at an average coefficient of 0.3 has A = 100 × 0.3 = 30 metric sabins. With a volume of 150 m³, RT60 = 0.161 × 150 ÷ 30 = 0.805 seconds.
Common mistakes
- Mixing units — the metric constant 0.161 requires area in m², volume in m³; the imperial Sabine constant is 0.049.
- Using one average coefficient for the whole room when surfaces differ greatly — sum each surface's own area × coefficient for accuracy.
- Applying Sabine's formula to very absorptive or oddly shaped rooms, where the Eyring formula is more appropriate.
Frequently asked questions
What is a good RT60 for a room?
It depends on use: roughly 0.3–0.5 s for a control room or small studio, 0.5–0.8 s for speech and classrooms, and 1.5–2.5 s for concert halls.
What is a metric sabin?
A metric sabin is the absorption equivalent of one square metre of a perfectly absorbing surface. Total absorption in sabins tells you how much sound energy the room's surfaces remove per reflection.
Related tools
- Noise Reduction Coefficient (NRC) Calculator
- Room Mode Calculator
- Frequency & Wavelength Calculator
- Sound Distance Attenuation Calculator
- Reverb Time (RT60) Calculator
- 70V/100V Line Speaker Load Calculator
Explore more in Audio, Acoustics & AV.
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.