RT60 Reverberation Time Calculator
Calculate reverberation time (RT60) using Sabine and Eyring formulas. Enter room dimensions, add surfaces with absorption coefficients, and get RT60 across frequency bands.
Room Dimensions
Surfaces & Absorption
RT60 Results
RT60 Targets by Room Type
About RT60 & Reverberation
RT60 (Reverberation Time) is the time it takes for a sound to decay by 60 dB after the source stops. It's the most fundamental measurement of a room's acoustic character. Long RT60 means a live, reverberant space (churches, concert halls). Short RT60 means a dry, absorptive space (recording studios, home theaters).
Sabine vs. Eyring Formula
The Sabine formula (RT60 = 0.161V/A) works well for rooms with low absorption (α < 0.3). It tends to overestimate RT60 in highly absorptive rooms. The Eyring formula (RT60 = −0.161V / (S × ln(1−ᾱ))) gives better results in rooms with high absorption and approaches 0 as absorption approaches 1 (anechoic).
Absorption Coefficient (α)
The absorption coefficient ranges from 0 (perfect reflector) to 1 (perfect absorber). Concrete and glass have α ≈ 0.02–0.05 at mid frequencies. Carpet has α ≈ 0.3–0.5. Acoustic foam (50mm) has α ≈ 0.7–0.9 at 1 kHz. The total absorption A = Σ(α × S) for all surfaces in Sabines (m²).