Your system
72 dB — inefficient
102 dB — very efficient
3 ft
30 ft
65 dB — quiet
105 dB — concert level
Results
Minimum watts needed
—
watts per channel
Max SPL from your amp
—
dB at listening position
Headroom above target
0 dB
+6 dB
+12 dB
+18 dB
+24 dB
Enter your amplifier's wattage above to see a full system assessment.
Shop amplifiers for your setup
Fosi Audio
Compact, high-value amplifiers — a favourite in the budget audiophile space
Browse amps →
Audio Advice
Curated selection of integrated and stereo amplifiers with expert guidance
Browse amps →
Amazon
Stereo and integrated amplifiers from leading audiophile brands with fast shipping
Browse amps →
Understanding the numbers
What does speaker sensitivity actually mean?
Speaker sensitivity is the sound pressure level (SPL) a speaker produces at one meter distance when driven with exactly one watt of power. A speaker rated at 90 dB sensitivity is twice as loud as an 87 dB speaker given the same input power — because every 3 dB represents a doubling of perceived loudness. This single spec determines more about how much amplifier you need than almost any other number.
Why do I need headroom above my target listening level?
Music is not a steady tone. Orchestral peaks, drum transients, and dynamic passages can exceed the average listening level by 10 to 20 dB. Without sufficient headroom, your amplifier reaches its maximum output during those peaks and clips — producing harsh distortion that stresses both your ears and your drivers. At least 10 dB of headroom above your typical listening level is advisable for dynamic music genres.
Does more wattage always mean better sound?
No. Wattage determines headroom and maximum volume, but it says nothing about the quality of the amplification. A well-designed 20-watt amplifier driving efficient 92 dB speakers can sound significantly better than a mediocre 200-watt design — the circuit topology, power supply quality, and output stage character matter at least as much as the rated power figure. Choose the wattage your setup genuinely needs, then prioritize amplifier quality within that range.
How does room size affect the calculation?
Smaller rooms reinforce bass frequencies and tend to build up SPL more readily than large, open spaces. A large room with high ceilings and absorptive materials can demand significantly more amplifier power to reach the same listening level as a small, lively room. The room gain adjustments in this calculator are approximations — your specific room's acoustic treatment, furnishings, and geometry will all influence the actual result.
Is the minimum wattage figure the right amp size to buy?
Treat the minimum as a floor, not a target. Amplifiers generally sound better when they are not being pushed close to their limits. If the calculator shows you need 20 watts minimum, a 50-watt amplifier will run more relaxed and typically offer better dynamics and lower distortion at your listening level. The sweet spot for most setups is 2 to 4 times the calculated minimum.
Related guides