Reverb Time Calculator

Reverb time is how long a sound takes to fade after the source stops.

It shapes the feel of every recording, live room, and mix. Too much reverb muddies speech. Too little makes music sound dry and lifeless.

Two core contexts define reverb time:

1. Acoustic reverb: the natural decay inside a physical room.
2. Musical reverb: the delay and decay synced to a song's tempo (BPM).

This calculator handles both, making it a complete toolkit for producers, engineers, and architects.

Why Sync Reverb to BPM?

Reverb that isn't tempo-synced can clash with the rhythm of a track.

When your decay time aligns to a musical subdivision, the reverb tail "breathes" with the music. It feels intentional rather than muddy.

Producers mixing electronic music, pop, and cinematic scores routinely sync reverb pre-delay to 1/16th or 1/8th note values.

How to Calculate Reverb Time?

In this Reverb Time Calculator, we used two main modes. Use one or both together.

Mode 1: Room Acoustic Reverb (RT60)

Enter your room's physical dimensions in feet or meters.

• Room length, width, and height.
• Select your surface material type (hard concrete, carpet, etc.).
• Hit Calculate Reverb Time.

You'll get the RT60 value; the time for sound to decay by 60 dB.

Results are compared against standard target values for your room type.

Mode 2: BPM-Synced Delay & Reverb

Enter your song's BPM and time signature.

• Choose a reverb size preset (Hall, Big Room, Small Room, Tight).
• Get delay times in milliseconds for every note division.
• Results include normal notes, triplets, and dotted notes.
• Hz values are shown for LFO users.

Sync your reverb pre-delay and decay perfectly to the beat.

Reverb Time Calculation Formulas

RT60: Sabine's Formula (Room Acoustics)

The classic formula for estimating reverberation time in a rectangular room:

RT60 = 0.161 × V / A

• V = Volume of the room in cubic meters (length × width × height)
• A = Total absorption in sabins (surface area × absorption coefficient)
• 0.161 = Constant derived from the speed of sound

For the 2kHz band, absorption coefficients vary by material. Hard surfaces (concrete, GWB) absorb very little. Soft surfaces (carpet, acoustic tiles) absorb much more.

BPM to Milliseconds

Quarter note delay time in ms:

Quarter Note (ms) = 60,000 ÷ BPM

All other note divisions are derived from this base value:

• Whole note = Quarter × 4
• Half note = Quarter × 2
• Eighth note = Quarter ÷ 2
• Sixteenth note = Quarter ÷ 4
• Triplet = Note value × (2/3)
• Dotted = Note value × 1.5

Hz conversion: Hz = 1000 ÷ ms

Reverb Pre-Delay & Decay

Pre-delay is typically set to a short note value (1/16 or 1/32 of a bar).

Decay time varies by reverb size preset:

• Hall: Pre-delay ~25ms, Decay ~2.5× quarter note
• Big Room: Pre-delay ~15ms, Decay ~2× quarter note
• Small Room: Pre-delay ~8ms, Decay ~1× quarter note
• Tight Ambience: Pre-delay ~3ms, Decay ~0.5× quarter note

Reverb Time Calculation (Practical) Example

Room Acoustic Example

Room: 30ft × 20ft × 10ft with hard concrete walls and tile floor.

• Volume = 6,000 cubic feet ? ~170 cubic meters
• Absorption (2kHz, hard room): ~0.05 coefficient
• Estimated RT60 ˜ 2.2 seconds
• This exceeds the Meeting Room target of 0.6–0.8s ? speech intelligibility will suffer.

BPM Delay Example

Song at 120 BPM, 4/4 time signature:

• Quarter note = 500ms
• Eighth note = 250ms
• Eighth note triplet = 166.7ms
• Dotted eighth = 375ms
• Hall pre-delay ˜ 25ms, Hall decay ˜ 1,250ms

Set your reverb pre-delay to 25ms and decay to 1,250ms for a tempo-locked hall effect at 120 BPM.

RT60 Target Values by Room Type

Use these benchmarks to evaluate your room's acoustic suitability:

• Classroom for hearing impaired: 0.5 seconds
• Church or theatre (speech/amplified music): 1.0 seconds
• Church or theatre (traditional music): 1.5–1.8 seconds
• Meeting rooms: 0.6–0.8 seconds
• Large convention facility: 1.5 seconds
• Gymnasium for teaching: 1.5–1.8 seconds
• Industrial buildings: 2.0–2.5 seconds
• Small arena (500–2,000 seats): 2.0 seconds
• Large arena (2,000+ seats): 2.75 seconds