Room Reverberation Time (RT60) Estimator
Predict how long sound lingers in a room by combining volume, surface area, and absorption. Enter dimensions, a weighted average absorption coefficient, and choose Sabine (0) or Eyring (1) to estimate RT60 in seconds.
Field measurements are recommended before finalising acoustic treatments.
Examples
- 8×5×3 m room, α = 0.20, Sabine ⇒ 0.61 seconds (small classroom).
- 12×7×4 m room, α = 0.35, Eyring ⇒ 0.39 seconds (treated lecture hall).
- 6×4×2.8 m studio, α = 0.55, Eyring ⇒ 0.25 seconds suitable for voice-over work.
FAQ
When should I use the Eyring formula?
Use Eyring for highly absorptive rooms (α > 0.3) where Sabine tends to under-predict decay time.
What if surfaces have different materials?
Calculate a weighted average absorption coefficient based on each surface area and material coefficient.
Does RT60 vary by frequency?
Yes. This calculator provides a broadband estimate; measure octave bands for detailed acoustic design.
How does furniture affect RT60?
Soft furnishings increase absorption. Update the coefficient when adding seating, curtains, or acoustic treatments to refine the estimate.
Additional Information
- Sabine formula: RT60 = 0.161 × Volume ÷ (α × Surface Area).
- Eyring accounts for highly absorptive spaces using a logarithmic correction when α > 0.3.
- Keep all dimensions in metres; if you measure in feet, convert before entering values so the 0.161 constant remains valid.
- Gather absorption coefficients from manufacturer datasheets for treatments like acoustic panels, carpeting, or upholstered seating.
- After modelling, verify the space with on-site RT60 measurements (MLS or sine sweep) to fine-tune acoustic treatment layouts.