🔊 How Loud Is Too Loud? (Decibel–Energy Converter)

Enter a sound level in dB (SPL) or intensity. Pick a distance and directivity to estimate source power (watts). See energy over time and friendly comparisons. Private, classroom-safe.

Your Inputs

dB SPL number, e.g., 85
Used to estimate source acoustic power from the measured intensity.
Seconds (e.g., 3600 = 1 hour)

Results

Level at microphone – dB SPL
Intensity at mic – W/m²
Pressure RMS – Pa
Estimated source acoustic power – W
Energy over time (at mic) – J/m²
Total energy emitted – J
Assumes plane-wave equivalence (p₀=20 µPa, I₀=1e−12 W/m²), ρ≈1.204 kg/m³, c≈343 m/s, spherical spreading with chosen directivity.
Pointer shows your level versus rough benchmarks (quiet room → pain threshold). Benchmarks are illustrative, not safety rules.

How we convert decibels to watts (friendly acoustics)

Decibels are a log scale. For intensity, L = 10·log₁₀(I / I₀) with I₀ = 1×10⁻¹² W/m². For pressure, L = 20·log₁₀(p / p₀) with p₀ = 20 µPa. In a simple plane wave, these two tie together via the characteristic impedance of air: I ≈ p² / (ρ·c), where ρ is air density and c is sound speed.

From dB → intensity: I = I₀ · 10^(L/10)
From intensity → pressure: p = sqrt(I · ρ · c)
Approx source power P from intensity I at distance r:
  I ≈ (Q · P) / (4π r²)  →  P ≈ I · (4π r²) / Q
Where Q is a directivity factor (Q=1 free field, Q=2 half-space, Q=4 quarter-space, or Q=10^(DI/10)).

Real rooms add reflections and standing waves; wind, humidity, and temperature also matter. Treat this as a learning tool for intuition, not a lab instrument.

Friendly comparisons (ballpark only)

  • Quiet room: ~30 dB
  • Conversational speech (1 m): ~60 dB
  • Busy street: ~80–85 dB
  • Lawnmower (close): ~90 dB
  • Rock concert (near stage): ~110 dB
  • “Pain threshold” for many people: ~120–130 dB

Comparisons vary by environment and equipment. Always follow local hearing-safety guidance for real decisions.

Hearing safety 💛

  • Loudness and time both matter. Even short bursts can add up over a day.
  • Quick check: if you have to raise your voice to talk to someone 1 m away, it’s probably too loud for long stays.
  • Increase distance. In open air, doubling your distance often lowers level by roughly ~6 dB (ballpark).
  • Protect your ears. Use earplugs or earmuffs at loud events or around power tools; take listening breaks.
  • Listen to your ears. Ringing, muffled hearing, or discomfort are warning signs—reduce volume and give yourself quiet time.

This tool is educational and not a sound-level meter or medical advice. Follow your local guidance for hearing protection and exposure limits.

5 Fun Facts about Loudness

10 dB ≈ “twice as loud”

Your ears hear a ~10 dB jump as double loudness even though physical intensity is 10×. Slide the dB input from 70 to 80 to watch watts shoot upward.

Psychoacoustics

Rock show ≈ night light

A raging 110 dB concert might radiate just a few acoustic watts—similar to a tiny lamp. Check the “source power” line to see how small it looks in watts.

Acoustic punch

Distance is a volume knob

Doubling distance cuts intensity about 4× (≈6 dB). Change the distance field from 1 m to 2 m and watch intensity and energy totals drop instantly.

Inverse square

Pressure is tiny

120 dB “ear-splitting” sound has only ~20 Pa RMS pressure—like the weight of a postcard on your hand. Peek at “Pressure RMS” to appreciate that scale.

Micro pushes

Energy sneaks up

An hour at 95 dB dumps over 10,000 J/m² onto your ears. Increase the exposure time field and see the “Energy over time” value balloon.

Dose matters

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