Standing wave ratio to percent power reflected
Type a value in SWR to get it in % instantly.
4%
That's about the same as a good match. About 4% of the power is reflected back.
Convert the other way: % to SWR
What it means
How good is that match?
SWR is measured at the meter, not at the antenna. Feeder loss flatters the reading: a long lossy cable can make a bad antenna look well matched.
The math
How to convert SWR to %
Everything comes from the reflection coefficient: Γ = (SWR − 1) ÷ (SWR + 1). Return loss is −20 × log₁₀(Γ) and the reflected power is Γ² × 100 percent.
Example: 1.5 SWR = 4 %.
Every unit
Your match in every unit
Tables
SWR to % conversion table
| SWR | % |
|---|---|
| 1.01 SWR | 0.00247519 % |
| 1.1 SWR | 0.226757 % |
| 1.2 SWR | 0.826446 % |
| 1.5 SWR | 4 % |
| 1.75 SWR | 7.43802 % |
| 2 SWR | 11.1111 % |
| 2.5 SWR | 18.3673 % |
| 3 SWR | 25 % |
| 4 SWR | 36 % |
| 5 SWR | 44.4444 % |
| 10 SWR | 66.9421 % |
% to SWR conversion table
| % | SWR |
|---|---|
| 1.01 % | 1.22345 SWR |
| 1.1 % | 1.23434 SWR |
| 1.2 % | 1.24604 SWR |
| 1.5 % | 1.27914 SWR |
| 1.75 % | 1.30491 SWR |
| 2 % | 1.32943 SWR |
| 2.5 % | 1.37562 SWR |
| 3 % | 1.41898 SWR |
| 4 % | 1.5 SWR |
| 5 % | 1.57601 SWR |
| 10 % | 1.92495 SWR |
Quick answers
Quick answers
- How many % is 1 SWR?
- 1 SWR is 0 %.
- How many % is 10 SWR?
- 10 SWR is 66.9421 %.
- How many % is 1.5 SWR?
- 1.5 SWR is 4 %.
The units
About these units
Standing wave ratio (SWR)
The ratio of voltages along the feeder. 1:1 is perfect.
Percent power reflected (%)
The share of transmitter power that never leaves.
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