Speaker Wattage Calculator
Calculate the speaker wattage needed for your room or venue.
Match amplifier power to speaker requirements.
Recommended Wattage
Speaker wattage needs depend on room size, speaker sensitivity, and desired volume.
The key formula:
Required Power = 10^((Desired SPL − Sensitivity + 20 × log10(Distance)) / 10)
Simplified room-based estimates:
- Small room (up to 200 sq ft / 18 sq m): 25–50W
- Medium room (200–500 sq ft / 18–46 sq m): 50–100W
- Large room (500–1000 sq ft / 46–93 sq m): 100–250W
- Small venue (1000–3000 sq ft / 93–280 sq m): 250–500W
- Large venue (3000+ sq ft / 280+ sq m): 500W+
Speaker sensitivity (measured in dB at 1W/1m):
- Low sensitivity: 84–87 dB (needs more power)
- Average: 87–90 dB
- High sensitivity: 90–95 dB (needs less power)
Doubling power adds only 3 dB. Going from 50W to 100W barely increases perceived volume. Going from 50W to 500W (10×) doubles perceived loudness.
Amplifier headroom: Your amp should have 50–100% more power than needed to handle peaks without distortion.