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DBm - dBw Watts Conversion Chart

DBm - dBw Watts Conversion Chart

Terms like dBW and dBm are widely used within radio frequency engineering as the measure of power.

The power levels expressed in dBm or dBW may not always be as meaningful as power expressed in watts and therefore a simple conversion chart converting dBm to watts and dBW and vice versa can be very useful.

Many power levels themselves for power meters, spectrum analysers, signal generators are specified in dBm or dBW rather than watts. Also RF components such as mixers, oscillators and the like, as well as the interfaces between modules in RF equipment have their levels specified in dBm or dBW. Radio transmitters may also have their output levels expressed in terms of dBW.

DBm and dBW - the basics

A decibel is not an absolute level - it is a comparison between two levels, and on its own it cannot be used to measure an absolute level. As a result of this the quantities of dBm and dBW are used:

  • dBm - This is a power expressed in decibels relative to one milliwatt.
  • dBW - This is a power expressed in decibels relative to one watt.

From this it can be seen that a level of 10 dBm is ten dB above one milliwatt, i.e. 10 mW. Similarly a power level of 20 dBW is 100 times that of one watt, i.e. 100 watts.

A more extensive conversion chart of dBm, to dBW and to watts is given below:

DBm to dBW & watts chart

The chart below gives a tabulation of dBm to dBW and watts which can be useful in determining some quick rough estimates of the values of power in different formats.

dBm to dBW & Watts Conversion Chart
dBmdBWWattsTerminology
+100+7010 000 00010 Megawatts
+90+601 000 0001 Megawatt
+80+50100 000100 kilowatts
+70+4010 00010 kilowatts
+60+301 0001 kilowatt
+50+20100100 watts
+40+101010 watts
+30011 watt
+20-100.1100 milliwatts
+10-200.0110 milliwatts
0-300.0011 milliwatt
-10-400.0001100 microwatts
-20-500.0000110 microwatts
-30-600.0000011 microwatt
-40-700.0000001100 nanowatts
-50-800.0000000110 nanowatts
-60-900.0000000011 nanowatt

With use the terms dBm, and dBW come to have their meaning and mentally it is possible to convert between them. However it is always useful to have a conversion table or chart to hand to be able to convert one to another.


Watch the video: Physics - Mechanics: Sound and Sound Waves 9 of 47 Decibel Scale Conversion (January 2022).