mW to dBm Conversion Calculator

mW to dBm Calculator

Enter power in milliwatts:

dBm result: dBm

A mW to dBm calculator converts power measurements between milliwatts (mW) and decibel-milliwatts (dBm), a logarithmic unit used in RF engineering, telecommunications, and signal analysis.

Key Definitions

• Milliwatt (mW): Linear power unit (1 mW = 0.001 W)

• dBm: Decibels relative to 1 mW (0 dBm = 1 mW)

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Conversion Formulas

1. mW to dBm

$$P(dBm)=10\times {\log }_{10}(P(mW))$$

Example:

• Convert 100 mW to dBm:

  $$10\times {\log }_{10}(100)=20\text{ dBm}$$

2. dBm to mW

$$P(mW)={10}^{\left(\frac{P(dBm)}{10}\right)}$$

Example:

• Convert 10 dBm to mW:

  $${10}^{(10\mathrm{/}10)}=10\text{ mW}$$

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Conversion Table (mW ⇆ dBm)

Milliwatts (mW)	dBm
0.001 mW	-30 dBm
0.01 mW	-20 dBm
0.1 mW	-10 dBm
1 mW	0 dBm
10 mW	10 dBm
100 mW	20 dBm
1000 mW (1 W)	30 dBm

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How to Use the Calculator

1. Enter mW → Get dBm (Take 10 × log₁₀(mW))

2. Enter dBm → Get mW (Calculate 10^(dBm/10))

Example Calculations:

• 5 mW to dBm:

  $$10\times {\log }_{10}(5)\approx 6.99\text{ dBm}$$

• -3 dBm to mW:

  $${10}^{(-3\mathrm{/}10)}\approx 0.501\text{ mW}$$

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Practical Applications

✅ WiFi/5G Signals (Typical router: 20 dBm = 100 mW)
✅ Fiber Optics (Laser power: 0 dBm = 1 mW)
✅ Cellular Networks (Phone transmission: 23 dBm ≈ 200 mW)
✅ Audio Equipment (Line levels: -10 dBm ≈ 0.1 mW)

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Key Reference Points

Power Level	dBm	mW
Max WiFi	30 dBm	1000 mW (1W)
Standard WiFi	20 dBm	100 mW
Bluetooth	0 dBm	1 mW
Minimum signal	-80 dBm	0.0000001 mW

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FAQ

1. Is 0 dBm equal to 0 Watts?

❌ No – 0 dBm = 1 mW = 0.001 W

2. Why use dBm instead of mW?

🔹 Logarithmic scale simplifies large/small values (e.g., -70 dBm vs. 0.0000001 mW)
🔹 Power ratios become simple additions/subtractions

3. How many dBm is 1 Watt?

✅ 1 W = 1000 mW = 30 dBm

4. What does negative dBm mean?

🔹 Power levels below 1 mW (e.g., -10 dBm = 0.1 mW)

5. How to convert 50 mW to dBm?

$$10\times {\log }_{10}(50)\approx 16.99\text{ dBm}$$