Coaxial Cable Loss Calculator

Work out coaxial cable loss instantly with clear inputs, formula shown and shareable results.

About Coaxial Cable Loss Calculator

Cable loss is proportional to length, so scale the per-100-metre figure directly. Loss rises roughly with the square root of frequency because of skin effect, so the same cable that loses 3 dB per 100 m at 100 MHz loses around 10 dB at 1 GHz.

Formula

Cable loss

loss(dB) = loss per 100 m x length / 100; power ratio = 10^(-loss/10)

Worked example

With the default values below, Coaxial Cable Loss Calculator returns Total cable loss of 3.60. Change any input above and every figure here is recalculated in your browser.

Inputs used

Cable length: 30 m
Loss per 100 m at the frequency: 12 dB
Frequency: 1,000 MHz
Input power: 25 W

Results

Total cable loss: 3.60 dB
Power at the far end: 10.91 W
Power efficiency: 43.65% %
Power lost as heat: 14.09 W

Step by step

1Values used
2Cable loss
3Total cable loss= 3.60 dB
4Power at the far end= 10.91 W
5Power efficiency= 43.65 %
6Power lost as heat= 14.09 W

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax or fees or charges into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why does loss rise with frequency?

Skin effect confines current to a thinner surface layer, raising effective resistance as the square root of frequency, plus dielectric losses that rise linearly.

Does cable loss affect receive as well as transmit?

Yes, and it is worse: the loss adds directly to the system noise figure, degrading sensitivity as well as reducing signal.