Decibel Calculator

Converts ratios to decibels using logarithmic scales. Power ratios use factor of 10, while voltage/current ratios use factor of 20 due to the square relationship between power and voltage.

1. 1

   Step 1

   Select calculation type (power or voltage/current ratio)

2. 2

   Step 2

   Enter the two values to compare

3. 3

   Step 3

   View the result in decibels

4. 4

   Step 4

   Or enter dB to find the ratio

• 1

  +3 dB = double power, +6 dB = double voltage

• 2

  -3 dB = half power (common filter cutoff)

• 3

  0 dB = equal values (ratio of 1:1)

• 4

  dBm = decibels relative to 1 milliwatt

• Using voltage formula (20 log) for power ratios

• Confusing dB with dBm or dBW (different references)

• Not accounting for impedance when converting voltage to power

• Adding dB values when ratios should be multiplied