Sound Intensity Decibel Calculator
Sound level in decibels from intensity or distance.
Enter your values
Enter the source power in W.
Enter the distance from source in m.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Sound level
- 95 dB
- Intensity
- 3.183e-3 W/m²
- Distance
- 5 m
Quick answer
Sound level (dB) = 10 x log10(I / I0), with I0 = 1e-12 W/m^2.
L = 10 log10(I/I0)
At a glance
| What it does | Sound level in decibels from intensity or distance. |
|---|---|
| Category | Physics |
| Inputs needed | Source power, Distance from source |
| Main output | Sound level |
| Formula | L = 10 log10(I/I0) |
| Cost | Free — no sign-up, no download |
How to use the Sound Intensity Decibel Calculator
- 1Enter the acoustic power of the source and the listening distance.
- 2The calculator spreads the power over a sphere to get intensity, then converts to decibels.
- 3Compare the result against common reference levels (60 dB conversation, 120 dB pain threshold).
Inputs explained
- Source power(W)
- Enter the source power in W.
- Distance from source(m)
- Enter the distance from source in m.
Worked example
Using the values the calculator loads with:
Inputs
- Source power1 W
- Distance from source5 m
Results
- Sound level95 dB
- Intensity3.183e-3 W/m²
- Distance5 m
Frequently asked questions
Why does doubling distance drop the level by 6 dB?
Intensity falls with the square of distance, and each doubling of intensity is about 3 dB, so distance doubling is about 6 dB.
Is this the same as loudness?
Decibels measure physical intensity; perceived loudness also depends on frequency and human hearing sensitivity.
What do I need to enter into the Sound Intensity Decibel Calculator?
Just 2 values: source power, distance from source. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Sound Intensity Decibel Calculator work out the answer?
Sound level (dB) = 10 x log10(I / I0), with I0 = 1e-12 W/m^2. It applies the formula L = 10 log10(I/I0) and shows the working so you can check each step by hand.
Is the Sound Intensity Decibel Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.