The dB ↔ Percentage Calculator helps users quickly convert decibels (dB) to percentage and vice versa. Decibels represent a logarithmic scale commonly used in audio engineering, telecommunications, signal processing, and physics to measure changes in power, voltage, current, or amplitude.
Since decibels are not linear, converting them into a percentage requires logarithmic calculations. This calculator simplifies these conversions, making it easier to understand signal gains, losses, and power changes.
Formula for Db ↔ Percentage Calculator
1. Convert dB to Percentage
For Power Gain/Loss:
Since decibels measure a logarithmic change in power, the percentage change is calculated as:
Percentage Change (%) = (10^(dB / 10) – 1) × 100
For Voltage, Current, or Amplitude Gain/Loss:
When measuring voltage, current, or amplitude changes, the formula is:
Percentage Change (%) = (10^(dB / 20) – 1) × 100
2. Convert Percentage to dB
For Power Change:
To find the decibel change from a percentage increase or decrease in power:
dB = 10 × log10(1 + (Percentage / 100))
For Voltage, Current, or Amplitude Change:
For voltage, current, or amplitude percentage change:
dB = 20 × log10(1 + (Percentage / 100))
Reference Table – Common dB to Percentage Conversions
To make conversions easier, here is a pre-calculated reference table for commonly used dB values:
| Decibels (dB) | Power Change (%) | Voltage/Amplitude Change (%) |
|---|---|---|
| -20 dB | -99% | -90% |
| -10 dB | -90% | -68% |
| -6 dB | -75% | -50% |
| -3 dB | -50% | -29% |
| 0 dB | 0% | 0% |
| +3 dB | +100% | +41% |
| +6 dB | +300% | +100% |
| +10 dB | +900% | +216% |
| +20 dB | +9900% | +900% |
This table allows audio engineers, sound technicians, and electronics professionals to quickly estimate signal strength changes without manually calculating.
Example of Db ↔ Percentage Calculator
1. Convert +6 dB to Percentage (Voltage Gain)
Using the voltage formula:
Percentage Change (%) = (10^(6 / 20) – 1) × 100
Percentage Change (%) ≈ (2 – 1) × 100 ≈ 100% increase
This means a +6 dB gain doubles the voltage or amplitude.
2. Convert 50% Power Increase to dB
Using the power formula:
dB = 10 × log10(1 + (50 / 100))
dB = 10 × log10(1.5) ≈ 1.76 dB
This means a 50% power increase corresponds to approximately +1.76 dB.
Most Common FAQs
Decibels provide a logarithmic scale, which makes it easier to express large variations in power, signal strength, and intensity. A small dB change can represent a large percentage change, making it ideal for fields like audio processing and telecommunications.
Power uses a factor of 10, while voltage and amplitude use a factor of 20 in logarithmic calculations. This is because power is proportional to the square of voltage.
Yes! Negative dB values represent a loss in power or amplitude, meaning the signal strength is decreasing compared to the reference level.