About The Signal Attenuation dB Calculator

The Signal Attenuation dB Calculator converts input and output power into attenuation in decibels, output/input ratio, and power loss percentage.

How to Use the Attenuation Calculator Online

1. Enter input power and output power using the same unit.
2. Run the calculator to see attenuation, ratio, and power loss.
3. Use the result with measurement notes for links, cables, filters, or RF paths.

Choosing Options Correctly

Use consistent power units. This calculation assumes power ratio, not voltage ratio. Measurement bandwidth, impedance, connectors, calibration, and noise floor can affect real results.

Common Use Cases

• Estimate cable or filter insertion loss.
• Convert measured input/output power into dB loss.
• Check signal budget assumptions.

Quick FAQ

Can output power exceed input power?
Yes if the entered dB value represents gain instead of attenuation. For loss, output should be lower than input.

Can I enter watts instead of milliwatts?
Use the units expected by the field or convert first. dB ratios are unitless, but absolute power fields must be consistent.

Does it include impedance mismatch?
No. Reflections, VSWR, cable frequency response, connectors, and impedance mismatch are separate RF or signal integrity concerns.

Why do small dB changes matter?
A 3 dB change is roughly a factor of two in power, so rounding can be significant in link budgets.