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The conversion of 18 dBm results in approximately 0.0631 watts.
This is calculated by converting decibel-milliwatts to watts. The formula involves exponentiating 10 to the power of (dBm value minus 30) divided by 10, effectively changing the logarithmic scale into a linear power measurement.
Conversion Result
Converting 18 dBm to watts gives about 0.0631 W.
Conversion Tool
Result in watts:
Conversion Formula
The formula to convert dBm to watts is: P (watts) = 10^((dBm – 30) / 10). It works because decibels are logarithmic, so reversing the log gives the linear power. For example, 18 dBm: 10^((18 – 30)/10) = 10^(-1.2) ≈ 0.0631 watts, showing how power scales with dBm.
Conversion Example
- Convert 10 dBm:
- Calculate (10 – 30)/10 = -2
- Then 10^(-2) = 0.01 watts
- Convert 0 dBm:
- (0 – 30)/10 = -3
- 10^(-3) = 0.001 watts
- Convert 25 dBm:
- (25 – 30)/10 = -0.5
- 10^(-0.5) ≈ 0.3162 watts
- Convert 5 dBm:
- (5 – 30)/10 = -2.5
- 10^(-2.5) ≈ 0.00316 watts
- Convert 40 dBm:
- (40 – 30)/10 = 1
- 10^1 = 10 watts
Conversion Chart
| dBm | Watts |
|---|---|
| -7.0 | 0.0002 |
| -6.0 | 0.00025 |
| -5.0 | 0.00032 |
| -4.0 | 0.00040 |
| -3.0 | 0.00050 |
| -2.0 | 0.00063 |
| -1.0 | 0.00079 |
| 0.0 | 0.001 |
| 1.0 | 0.00126 |
| 2.0 | 0.00158 |
| 3.0 | 0.002 |
| 4.0 | 0.00251 |
| 5.0 | 0.0032 |
| 10.0 | 0.01 |
| 20.0 | 0.1 |
| 30.0 | 1 |
| 40.0 | 10 |
| 43.0 | 17.8 |
Use this chart to quickly look up the watt value for a given dBm from -7 to 43, useful for quick estimations without calculator.
Related Conversion Questions
- How many watts correspond to 18 dBm in different systems?
- What is the watt equivalent for 18 dBm in RF applications?
- How do I convert 18 dBm to milliwatts?
- Is 18 dBm considered high power for wireless devices?
- What is the difference between 18 dBm and 0.5 watts?
- Can I convert 18 dBm to volts directly?
- What does 18 dBm mean in terms of signal strength?
Conversion Definitions
dbm
Decibel-milliwatts (dBm) is a logarithmic unit indicating power level relative to one milliwatt, used mainly in radio, telecommunications, and audio systems to express signal strength in a compact form.
watts
Watts are a basic unit of power measurement in the International System, representing the rate of energy transfer or consumption per second, used in electrical, mechanical, and thermal contexts to quantify energy flow.
Conversion FAQs
What does 18 dBm mean in terms of signal power?
18 dBm indicates a signal power of about 0.0631 watts, which is moderate power level used in Wi-Fi and other wireless communications. It reflects how strong or weak a signal is compared to the standard reference point of 1 milliwatt.
How accurate is converting dBm to watts with this formula?
The formula is mathematically precise, based on logarithmic to linear conversion, but real-world measurements might vary slightly due to factors like equipment calibration and environmental conditions.
Can I convert any dBm value to watts with this method?
Yes, this formula applies to any dBm value, allowing you to calculate the equivalent watts directly, assuming the measurement is correct and the units are consistent.
Why is 30 subtracted from the dBm value in the formula?
Because 0 dBm equals 1 milliwatt, and the formula converts the logarithmic value relative to 1 milliwatt by shifting the scale, so subtracting 30 adjusts the dBm to a power level in watts.
How do I convert watts back to dBm?
To convert watts to dBm, take 10 times the base-10 logarithm of the watt value, then add 30. The formula: dBm = 10 * log10(watts) + 30.