dBm to Watts Conversion
RF power conversion both ways
Required Parameters
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Quick Answer
dBm is an absolute power measurement referenced to 1 milliwatt (mW). 0 dBm = 1 mW. Every 3 dB increase doubles the power; a 10 dB increase multiplies power by 10.
Convertisseur dBm vers Watts
Convertissez entre dBm et watts pour les mesures de puissance RF.
Formules
P(mW) = 10^(dBm/10)
dBm = 10 x log10(P/1mW)
Outils Associes
- Calculateur d'Attenuateur
- Calculateur de Frequence vers Longueur d'Onde
Design Notes
Using dBm makes calculating signal chains incredibly simple by substituting multiplication/division with addition/subtraction. For example, if you output +10 dBm, pass it through a -3 dB attenuator, and add a +15 dB amplifier, the output is simply 10 - 3 + 15 = +22 dBm. Note that in 50Ω systems, 0 dBm corresponds to ~223.6 mV(RMS).
Common Mistakes
- 1
Confusing dBm (absolute power) with dB (relative ratio). You can add dB to dBm, but adding dBm to dBm is mathematically invalid.
- 2
Forgetting that negative dBm still represents positive Watts (e.g., -30 dBm is 1 microwatt, not 'negative power').
- 3
Assuming the calculation depends on impedance. Power to dBm conversion is pure power mapping independent of impedance, though converting it safely to Voltage requires knowing Z0.
Engineering Handbox
1. Use formula: P(W) = 10^(dBm / 10) / 1000 2. 10^(30/10) = 10³ = 1000 3. 1000 / 1000 = 1 Watt
Knowledge Base
Qu'est-ce que le dBm ?
Le dBm est une unité de puissance absolue référencée à 1 milliwatt. 0 dBm = 1 mW, +30 dBm = 1 W, −30 dBm = 1 µW. Chaque +3 dB double la puissance, chaque +10 dB la multiplie par 10.
Comment convertir des dBm en watts ?
P(W) = 10^(dBm/10) / 1000. Exemple : +20 dBm = 10^(20/10) / 1000 = 100 mW. Inversement : dBm = 10 × log10(P_mW). C'est l'unité standard en télécommunications et RF.