RT60 Reverb Decay Calculator
Estimate room reverb decay time (RT60) using the Sabine formula for quick acoustic planning.
Equivalent Absorption = (Average Coefficient × Total Surface Area) + Extra Absorption
What is reverb decay (RT60)?
Reverb decay, usually expressed as RT60, is the time it takes for a sound in a room to decay by 60 dB after the source stops. In practical terms, it tells you how “live” or “dead” a room sounds. Long RT60 values can make speech muddy and mixes unclear, while very short values can make a space feel unnaturally dry.
Why use a reverb decay calculator?
A reverb decay calculator gives you a fast, useful estimate for room acoustics before you spend money on treatment. It helps with:
- Home studio setup and acoustic panel planning
- Podcast and voice-over room tuning
- Classroom and meeting room intelligibility
- Small venue sound design and comfort
How this calculator works
1) Room volume
The calculator multiplies length × width × height to get room volume in cubic meters.
2) Total surface area
It computes all six room surfaces (floor, ceiling, and four walls) to estimate how much area can absorb sound.
3) Equivalent absorption
The average absorption coefficient (0 to 1) is applied to total surface area. Then any added absorption (furniture, people, panels, heavy curtains, etc.) is added as extra sabins.
4) RT60 estimate
Using the Sabine equation, it estimates decay time. This model is most reliable in reasonably diffuse rooms and gives a solid first-pass target for acoustic treatment decisions.
Typical RT60 targets by room type
- Voice booth: 0.2–0.4 s
- Podcast / streaming room: 0.25–0.45 s
- Small control room: 0.3–0.5 s
- Living room media space: 0.4–0.7 s
- Classroom: 0.4–0.8 s
- Small church / hall: 1.0–2.0 s (depends on use)
How to lower RT60 effectively
If your calculated decay is too high, increase absorption in a balanced way:
- Add broadband wall panels at first reflection points
- Use bass traps in corners for low-frequency control
- Install thick curtains and rugs to reduce high-frequency ringing
- Include soft furniture to raise overall absorption
- Avoid over-deadening only one frequency range
Important limitations
This calculator is intentionally simple and ideal for planning. Real-world results vary with frequency, room shape, diffusion, furniture distribution, and construction materials. For critical spaces, verify with acoustic measurement tools (such as impulse response testing) and adjust treatment iteratively.
Quick takeaway
Use this reverb decay calculator to get a practical RT60 estimate, set a target, and identify how much extra absorption you need. It is one of the easiest ways to make better decisions in room acoustics, sound treatment, and recording quality.