How many dB does it take to double the volume?

Doubling the amplitude (×2) requires +6.02 dB. However, perceived loudness (psychoacoustic doubling) is closer to +10 dB because human hearing is logarithmic.

What is the difference between amplitude and power dB formulas?

Amplitude (voltage, SPL) uses dB = 20 × log₁₀(ratio). Power uses dB = 10 × log₁₀(ratio). For most audio work — microphone levels, speaker SPL, DAW faders — the 20× formula applies.

What does "50% louder" mean in dB?

A 50% increase means the amplitude ratio is 1.5. Applying the formula: 20 × log₁₀(1.5) ≈ 3.52 dB.

Why is dB on a logarithmic scale?

Human hearing perceives loudness logarithmically. A sound must be roughly 10× more powerful to be heard as twice as loud. The logarithmic dB scale matches this perception, keeping numbers practical (e.g. 0–120 dB instead of 1–1,000,000,000,000).

Can I use this for speaker SPL calculations?

Yes. SPL is an amplitude quantity, so dB = 20 × log₁₀(amplitude ratio) applies directly. Enter your desired SPL increase as a multiplier (e.g. ×3.16 for +10 dB).

Audio Volume Booster Calculator

Audio engineering calculator: enter a volume boost percentage or ratio to calculate the exact dB gain required, with decibel formulas explained.

Volume Boost Input

Boost mode

Percentage increase Amplitude multiplier

Percentage increase (%)

dB formula

20 × log₁₀ (amplitude / SPL) 10 × log₁₀ (power / intensity)

Quick examples

Result

Enter a boost value and click Calculate

Summary

Audio engineering calculator: enter a volume boost percentage or ratio to calculate the exact dB gain required, with decibel formulas explained.

How it works

Choose whether you are entering a percentage increase or a direct ratio, then select whether that input describes amplitude/SPL or power/intensity.
Enter the boost amount in the input field.
The calculator converts your input to a ratio of the selected quantity.
It applies dB = 20 × log₁₀(ratio) for amplitude/SPL or dB = 10 × log₁₀(ratio) for power/intensity.
Results show the required dB value, the amplitude ratio, and the power ratio.
The step-by-step panel explains each calculation so you can reproduce it manually.

Use cases

Find how many dB of gain your amplifier needs to double perceived loudness.
Determine the exact gain setting when normalizing audio clips by percentage.
Understand decibel relationships when mixing or mastering music.
Convert a "make it 3× louder" request into a precise gain value for your DAW.
Learn the dB math for acoustics homework or audio engineering study.
Verify amplifier specs when selecting hardware for a speaker system.

Frequently Asked Questions

Last updated: 2026-09-22 · Reviewed by Nham Vu