Room Reverberation and Absorption Area Calculator
Estimate Sabine reverberation time and the replacement surface area needed for an entered target decay time.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Sum each surface area multiplied by its entered absorption coefficient. Apply the Sabine estimate. Treating part of one selected surface replaces its existing coefficient, so only the coefficient difference adds absorption.
A=sum(area×absorption coefficient); RT60≈0.161V/A; treatment area=(0.161V/target−A)/(new coefficient−old coefficient)
Worked example
A 50 m³ room with 85 m² of surfaces all at coefficient 0.05 has A=4.25 m² and RT60≈1.8941 s. Replacing 15.8 m² of a 0.05 surface with coefficient 0.80 gives a modeled target of 0.5 s.
Assumptions and input details
Enter all coefficients at the same frequency band and mounting condition; no material database or universal target is supplied. Surface rows are disjoint areas. Available treatment cannot exceed the selected row. Diffuse-field Sabine estimate, generally more useful at low average absorption; strong absorption, uneven placement, room modes and non-diffuse rooms reduce accuracy. Air attenuation, scattering and source/listener position are omitted. Zero total absorption has no finite result. Required area is continuous, without panel-size rounding. A target may be impossible within the available area.
References: Montana State University: Sabine RT60 · MathWorks: diffuse-field room assumptions
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
The 36 volume definitions distinguish US liquid, US dry and Imperial measures. Cups carry an explicit definition. Japanese shō is 2401/1331 L and a gō is one tenth of it; the explicitly labelled 180 mL rice cup is separate.
Regional measures are not interchangeable merely because their names look similar. This is a documented selection, not a claim to include every historical unit.
NIST measurement tables · UK Imperial definitions · Japanese traditional units · Mainland China and Hong Kong unit distinctions
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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