RT60 Reverberation Time Calculator
Reverberation time per octave band (125 Hz – 4 kHz), using both the Sabine and Eyring formulas, from your room and its surfaces. Compare against the target range for your use.
Surfaces
What is a good RT60? Target reverberation time by room
There is no single “correct” reverberation time — the target depends on what the room is for. These mid-band (500 Hz) RT60 ranges are the ones this calculator checks your room against; smaller rooms should aim for the lower end. Enter your dimensions above to see where your room lands per octave band.
| Use-case | Target RT60 @ 500 Hz |
|---|---|
| Mixing / critical listening | 0.2–0.3 s |
| Voice-over / podcast | 0.25–0.4 s |
| Home theatre | 0.3–0.5 s |
| Recording live room | 0.4–0.6 s |
| Office / conference | 0.4–0.6 s |
Typical RT60 for common untreated rooms
A quick reference for how live a bare small room is before treatment — the mid-band (500 Hz) figure, computed by the same engine as the calculator above for a furnished but acoustically untreated room (thin carpet floor, plasterboard walls, gypsum-board ceiling). Enter your own room and surfaces above for an exact per-band figure.
| Room | Size | RT60 @ 500 Hz |
|---|---|---|
| Bedroom studio | 3 × 2.4 × 2.4 m 10 × 8 ft | 0.98 s |
| Small home studio | 3.5 × 3 × 2.4 m 11.5 × 10 ft | 1.07 s |
| Typical project studio | 4 × 3 × 2.5 m 13 × 10 ft | 1.12 s |
| Medium control room | 4.5 × 3.5 × 2.7 m 15 × 11.5 ft | 1.24 s |
| Living room / home theatre | 5.5 × 4 × 2.7 m 18 × 13 ft | 1.32 s |
These are untreated starting points, not targets — every one sits well above the ranges in the table above. To bring a room down, start with the first-reflection points and corner bass traps, then size the rest with the acoustic panel calculator. RT60 measures broadband decay; it does not capture the low-frequency room modes that dominate the small-room bass problem — check those separately.
Sabine vs Eyring
Use Sabine for untreated or lightly-treated rooms (mean absorption below ~0.2). Use Eyring for treated studios and any room with significant absorption — Sabine over-predicts in those cases. Both formulas and the constant 0.161 are documented on the methodology page. Coefficients come from the material database, and this tool uses each material's full per-band curve — not its NRC — so the bass is handled honestly. For a panel you intend to build rather than one that has been measured, predict its curve first with the porous absorber calculator.
Frequently asked questions
What is a good RT60 for a room?
A good mid-band (500 Hz) RT60 is roughly 0.2–0.3 s for mixing and critical listening, 0.25–0.4 s for voice-over and podcasting, 0.3–0.5 s for a home theatre, and 0.4–0.6 s for a live room or office. Smaller rooms should aim for the lower end of each range — see the target table above.
How do I lower my room’s RT60?
Add broadband absorption: floor-to-ceiling corner bass traps first, then panels at the first reflection points, then more wall and ceiling coverage until the reverberation time drops into the target range. The acoustic panel calculator works out how much you need.
Should I use the Sabine or Eyring formula?
Use Sabine for untreated or lightly treated rooms (mean absorption below about 0.2) and Eyring for treated rooms; Sabine over-predicts once a room has significant absorption. This calculator reports both so you can compare.
What is RT60 (reverberation time)?
RT60 is the time in seconds for a sound to decay by 60 decibels after the source stops. It measures how long a room rings — a long RT60 makes speech muddy and mixing decisions unreliable.