Efficiency to dB Calculator

Switch between percent, ratio, or powers easily. See efficiency, dB gain, and dB loss fast. Download CSV or PDF to save your calculations today.

Choose the input type that matches your data.
More decimals show finer changes in dB.
Allowed range: 0 to 100.
η = Pout / Pin, typically between 0 and 1.
Use positive values only.
Output can be smaller than input for losses.
Reverse conversion uses η = 10^(dB/10).

Example Data Table

Efficiency (%) η (ratio) Efficiency (dB) Loss (dB)
100.10-10.000010.0000
250.25-6.02066.0206
500.50-3.01033.0103
750.75-1.24941.2494
900.90-0.45760.4576

These examples use dB = 10·log10(η). Efficiencies below 100% produce negative dB, while loss in dB is shown as a positive value.

Formula Used

  • Efficiency ratio: η = Pout / Pin
  • Percent to ratio: η = Efficiency(%) / 100
  • Efficiency in dB (power ratio): dB = 10 · log10(η)
  • Loss in dB: Loss(dB) = 10 · log10(Pin / Pout) = −dB
  • Reverse conversion: η = 10^(dB/10), Efficiency(%) = 100 · 10^(dB/10)

How to Use This Calculator

  1. Select a conversion method that matches your data.
  2. Enter efficiency as percent, ratio, power values, or dB.
  3. Pick the number of decimals you want to display.
  4. Press Calculate to view results above the form.
  5. Use Download CSV or Download PDF for reports.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.