Use P in watts = 10 raised to the power (dBm − 30)/10. This reverses the logarithmic dBm scale.
How it works in practice
A small dB change represents a multiplicative power change. Keep enough precision for the application without implying measurement accuracy beyond the instrument. Convert multiple powers to linear units before adding them. Ordinary power addition is not direct dBm addition.
Example and interpretation
27 dBm is about 0.501 W; −10 dBm is 0.0001 W, or 0.1 mW.
Checks before use
- Write the dBm value
- Subtract 30
- Divide by 10 and exponentiate
- Check units
Important limit
Do not add two dBm readings numerically to obtain total power.
Related Centron RF product
SMA 2 W 6 GHz fixed attenuator. Use calculated levels to define a requirement, then compare it with the exact product’s current bandwidth, input power, impedance and available attenuation options. Calculations assume stated conditions and do not replace a component datasheet.
Further reading
Keysight: Fundamentals of RF and Microwave Power Measurements. This background reference explains general principles; the selected Centron RF model’s datasheet governs its own ratings.
Related guides
Educational guide. Numerical examples use the stated assumptions and are not test results for a supplied unit.