How is decibel level (sound intensity) calculated?

Decibels use a logarithmic scale: dB = 10 × log10(intensity ÷ reference intensity), which is why decibel differences don't behave like simple linear numbers.

Why is the decibel scale logarithmic?

Human hearing perceives sound intensity logarithmically rather than linearly, and actual sound power spans an enormous range, so a log scale keeps the numbers manageable.

How much louder is 20 dB more than another sound?

Every 10 dB increase represents roughly a 10x increase in sound intensity (though perceived loudness roughly doubles per 10 dB), so 20 dB more is about 100 times more intense.

Decibel Calculator - CalculatorLabs.net

Decibel Calculator

Sound intensity level in decibels (dB) is a logarithmic scale that compares a sound's intensity to the quietest sound the human ear can detect.

Sound Intensity (W/m²)

Instant Result

Sound Level -

What Is a Sound Intensity / Decibel Calculator?

Sound intensity level in decibels (dB) is a logarithmic scale that compares a sound's intensity to the quietest sound the human ear can detect. Because it's logarithmic, every extra 10 dB represents a sound that's actually 10 times more intense. This calculator converts a raw sound intensity into decibels.

How to Use This Sound Intensity / Decibel Calculator

Measure or look up the sound intensity in watts per square meter (W/m²).
Enter that value into the field above.
Click Calculate to get the sound level in decibels, relative to the standard threshold of hearing (10⁻¹² W/m²).

Formula

Sound Level (dB) = 10 × log₁₀(I / I₀)
I₀ = 10⁻¹² W/m² (threshold of human hearing)

Worked Example

A sound has an intensity of 1×10⁻⁶ W/m². Sound Level = 10 × log₁₀(10⁻⁶ / 10⁻¹²) = 10 × log₁₀(10⁶) = 10 × 6 = 60 dB — roughly the level of normal conversation.