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RF Power Calculator

Convert RF power between watts, dBm, and dBW. Calculate power density and link budget components for ham radio and wireless.

Use this result well

Inputs that matter
Power Value, Input Unit
Output to expect
RF Power Converter
  • Check the units and required inputs before comparing results.
  • Keep the assumptions with a copied result so you can reproduce the calculation later.
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Reference & details

How it works

Watts to dBm

Convert watts to milliwatts (×1000), then take log10 and multiply by 10. 1W = 1000 mW = 30 dBm.

dBm = 10 × log10(P_mW)

dBm to Watts

Reverse conversion: divide dBm by 10, raise 10 to that power, divide by 1000 for watts. 37 dBm = 5W.

P (W) = 10^((dBm − 30) / 10)

dBW Reference

dBW references 1 watt. Useful for transmitter specs. 100W = 50 dBW = 80 dBm.

dBW = 10 × log10(P_W); dBm = dBW + 30

Updated: July 2026

Example Scenarios

5W = 37 dBm vs 100W = 50 dBm. Difference of 13 dB ≈ 2 S-units — significant in weak signal work but QRP contacts are routine.

Receiver rated 0.15 μV for 12 dB SINAD ≈ −123 dBm sensitivity — compare with calculated path loss for link budget.

Input 10W (40 dBm), output 100W (50 dBm) → gain = 10 dB. Verify linearity and heat dissipation at rated output.

FAQ

Decibels relative to 1 milliwatt. 0 dBm = 1 mW. 30 dBm = 1W. Standard unit for RF power in telecommunications and amateur radio specifications.

100W = 100,000 mW = 50 dBW = 80 dBm. Each 10 dB increase represents 10× power increase.

dBm references 1 mW; dBW references 1 W. dBm = dBW + 30. Use dBW for high-power transmitters, dBm for receivers and low-power circuits.

No. dBm is logarithmic — add dBm values only when combining power from uncorrelated sources. For gain/loss budgets, add dB values sequentially.

Limits vary by band and license class. US amateur: up to 1500W PEP on most HF bands (except 30m). Always verify current FCC Part 97 rules for your band.

About RF Power Calculator

RF power is expressed in watts (linear) or decibels relative to milliwatts/watts (logarithmic). Convert between W, mW, dBm, and dBW for link budget calculations, amplifier specifications, and receiver sensitivity comparisons.