Reverb Decay Time Calculator

Tune studio and hall sound with dependable estimates. Compare materials and see absorption change instantly. Design clearer mixes by targeting the right decay time.

The Sabine constant changes with units.
m
m
m
m³
Use this if the room is not a perfect box.
sabins
Seats, people, curtains, furniture, panels.
Surface materials (mid-frequency α)
Pick a preset, or set a custom coefficient.
Valid range: 0.00 to 1.00
α
Preset values are typical mid-frequency estimates.
α
Preset values are typical mid-frequency estimates.
α
Preset values are typical mid-frequency estimates.
α
Preset values are typical mid-frequency estimates.
Tip: RT60 changes with frequency. For better accuracy, calculate per octave band.

Example data table

Example uses a small room with carpet and an acoustic ceiling.
Units Length Width Height Floor α Ceiling α Walls α Extra sabins Estimated RT60 (s)
Metric 6.0 m 4.5 m 2.8 m 0.40 0.60 0.05 8 ≈ 0.28
Imperial 20 ft 15 ft 9 ft 0.10 0.05 0.03 0 ≈ 1.46

Formula used

This calculator uses the Sabine reverb time approximation:

V is volume, S is surface area, α is absorption coefficient, and A is absorption in sabins. The constant k is 0.161 (metric) or 0.049 (imperial).

How to use this calculator

  1. Select your unit system and enter room length, width, and height.
  2. Optionally enter an override volume for complex room shapes.
  3. Choose a material preset for each surface, or type α directly.
  4. Add extra sabins for furniture, people, or additional treatment.
  5. Press Calculate to see RT60 above the form and export results.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.