RT60 (Reverberation Time 60) is the number of seconds it takes for a sound to decay by 60 dB after the sound source stops. It is the standard metric for measuring room acoustics.

What is the Sabine formula?

The Sabine formula is RT60 = 0.161 × V / A, where V is the room volume in cubic meters and A is the total acoustic absorption in metric sabins (m²). It gives a good approximation for rooms with low to moderate absorption.

What absorption coefficient should I use?

Absorption coefficients range from 0 (perfectly reflective) to 1 (perfectly absorptive). Concrete or glass is around 0.02–0.05; carpet is 0.2–0.5; acoustic foam or heavy curtains can reach 0.7–0.99. Values vary by frequency — use mid-frequency (500 Hz–1 kHz) values for a general estimate.

What RT60 is ideal for a recording studio?

Control rooms typically target 0.2–0.4 s. Live rooms for tracking instruments often aim for 0.3–0.6 s. Speech-focused spaces like podcasting booths should be below 0.3 s.

When is the Sabine formula less accurate?

Sabine's formula assumes absorption is evenly distributed. For rooms where absorption exceeds roughly 20–25% of total surface area, the Eyring formula gives more accurate results. This calculator uses Sabine as it is the most widely taught and used starting point.

Reverb Time Calculator (RT60)

Enter room dimensions and surface absorption data to calculate RT60 reverberation time using the Sabine formula.

Room Dimensions

Length (m)

Width (m)

Height (m)

Calculated volume 60.0 m³

Surfaces & Absorption

Material / Label Area (m²) Coeff (α)

Total absorption (A) — m² sabins

Absorption Coefficient Reference

Material	α (500 Hz)

Click a row to use that coefficient in the last surface row.

RT60 Result

Reverberation Time (RT60)

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seconds

Typical RT60 Targets

Summary

Enter room dimensions and surface absorption data to calculate RT60 reverberation time using the Sabine formula.

How it works

Enter the room length, width, and height in meters to compute volume automatically.
Add one or more surfaces — specify the surface area (m²) and its absorption coefficient (0–1).
The tool sums all absorption values into total absorption A (in metric sabins).
RT60 is computed as 0.161 × V / A using the Sabine formula.
Results update instantly whenever any input changes.
Use the reference table for typical absorption coefficients of common materials.

Use cases

Estimate reverberation time when designing a recording studio or rehearsal room.
Check whether a conference room or classroom meets speech-intelligibility guidelines.
Compare how different wall treatments (foam, carpet, curtains) affect RT60.
Validate acoustic calculations before purchasing treatment panels.
Teach acoustics fundamentals using an interactive Sabine formula demo.
Quickly assess live venues or home theaters for reverb suitability.

Frequently Asked Questions

Last updated: 2026-09-22 · Reviewed by Nham Vu