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Reverberation Time Calculator

Work out reverberation time instantly with clear inputs, formula shown and shareable results.

About Reverberation Time Calculator

Sabine's equation gives the time for sound to decay by 60 dB: T60 = 0.161V/A, where A is surface area times average absorption. A 250 m3 room with 240 m2 of surface at 0.25 absorption reverberates for 0.67 s - good for speech. Adding absorption is the only way to shorten it, since volume is usually fixed.

Formulas

Sabine's equation

T60 = 0.161 V / (S x alpha)

Absorption

A = surface area x average absorption coefficient

Worked example

With the default values below, Reverberation Time Calculator returns Reverberation Time T60 of 0.671. Change any input above and every figure here is recalculated in your browser.

Inputs used

Room volumeminimum 0 m3
250 m3
Total surface areaminimum 0 m2
240 m2
Average absorption coefficientaccepts 0–1
0.25

Results

Reverberation Time T60
0.671 s
Total Absorption
60.000 m2 sabins
Acoustic Character
Balanced - good for multipurpose halls
Extra Absorption Needed For A One-Second T60
0.000 m2

Step by step

  1. 1Values used
  2. 2Sabine's equation
  3. 3Absorption
  4. 4Reverberation Time T60= 0.671 s
  5. 5Total Absorption= 60.000 m2 sabins
  6. 6Acoustic Character= Balanced - good for multipurpose halls
  7. 7Extra Absorption Needed For A One-Second T60= 0.000 m2

Assumptions and limits

  • The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

What T60 should a room have?

About 0.4-0.6 s for speech and studios, 1.0-1.4 s for a multipurpose hall, and 1.8-2.2 s for orchestral concert halls.

Why is my room boomy at low frequencies?

Absorption coefficients fall at low frequency, so T60 rises there. Bass traps and thick porous absorbers are needed rather than thin panels.

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