RF Link Budget, EIRP, Received Signal Strength (RSSI dBm) & Fade Margin Calculator

Compute EIRP (dBm), Received Signal Level (dBm), and Fade Margin (dB) over any wireless link.

Received Signal Level (RSL / RSSI)
-71 dBm
Link Fade Margin (RSL − Rx Sensitivity) 25 dB
Effective Isotropic Radiated Power (EIRP) 32 dBm
Transmitter Output Power 199.53 mW
Inputs
⚡ Scenarios:
dBm
Transmitter power in dBm (20 dBm = 100 mW, 30 dBm = 1 W).
dB net
Sum of Tx antenna gain + Rx antenna gain minus coax/connector loss (dB).
dB
Free-space + atmospheric/clutter path loss (dB).
dBm
Receiver minimum sensitivity threshold for target BER (dBm).
Results & Graph
Received Signal Level (RSL / RSSI)
-71 dBm
Link Fade Margin (RSL − Rx Sensitivity)
25 dB
Effective Isotropic Radiated Power (EIRP)
32 dBm
Transmitter Output Power
199.53 mW

Received Signal Level (RSL / RSSI)

Graph 1 • RF Link Budget & Fade Margin • Domain Architecture & Live Telemetry Maps Tx Output Power Dbm, Combined Antenna Gain Dbi, Total Path Loss Db through RF Link Budget & Fade Margin Formula.
Source / Tx Target / Rx RF Link Budget & Fade Margin Propagation Path Received Signal Level (RSL -71 dBm Link Fade Margin (RSL − Rx: 25 dB Effective Isotropic Radiat: 32 dBm
Graph 2 • Received Signal Level (RSL / RSSI) Across Tx Output Power Dbm Sweep (40% → 160%) Evaluates EIRP = P_tx_dBm + G_tx_dBi − L_cable_dB; RSL = EIRP − PathLoss_dB + G_ across 7 operating points (current input highlighted).
-84.80 dBm -41.85 dBm 1.10 dBm -84.80 9.20dBm -80.20 13.80dBm -75.60 18.40dBm -71 23dBm -66.40 27.60dBm -61.80 32.20dBm -57.20 36.80dBm
Graph 3 • Joint Sensitivity: Tx Output Power Dbm × Combined Antenna Gain Dbi Compares Received Signal Level (RSL / RSSI) when Combined Antenna Gain Dbi is shifted +25% (solid) vs. −25% (dashed).
-82.40 dBm -40.65 dBm 1.10 dBm --- Combined Antenna Gain Dbi @ 75% -73.40 -30% -69.95 -15% -66.50 +0% -63.05 +15% -59.60 +30%
Summary: With 23 dBm Tx power, +18 dB net antenna gain, and 112 dB path loss, Received Signal Level is -71 dBm, providing a 25 dB Fade Margin above -96 dBm sensitivity.
Summary: With 23 dBm Tx power, +18 dB net antenna gain, and 112 dB path loss, Received Signal Level is -71 dBm, providing a 25 dB Fade Margin above -96 dBm sensitivity.
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Formula & Mathematical Methodology: RF Link Budget & Fade Margin Formula

EIRP = PtxdBm + GtxdBi − LcabledB
RSL = EIRP − PathLossdB + GrxdBi
FadeMargin = RSL − RxSensitivity
EIRP = P_tx_dBm + G_tx_dBi − L_cable_dB; RSL = EIRP − PathLoss_dB + G_rx_dBi; FadeMargin = RSL − RxSensitivity
  • txOutputPowerDbm: Tx Output Power Dbm (dBm)
  • combinedAntennaGainDbi: Combined Antenna Gain Dbi (dB net)
  • totalPathLossDb: Total Path Loss Db (dB)
  • rxSensitivityThresholdDbm: Rx Sensitivity Threshold Dbm (dBm)

Rounding: Engineering outputs round to 2–3 decimal places; discrete material bag/unit counts round up via ceiling.

Worked Example: Engineering Scenario: RF Link Budget & Fade Margin

Compute EIRP (dBm), Received Signal Level (dBm), and Fade Margin (dB) over any wireless link.

  1. Enter your system dimensions, electrical/RF ratings, or environmental conditions.
  2. Evaluate the governing equation: EIRP = P_tx_dBm + G_tx_dBi − L_cable_dB; RSL = EIRP − PathLoss_dB + G_rx_dBi; FadeMargin = RSL − RxSensitivity.
  3. Inspect the primary design output, supporting allowances, and 3 SVG schematics.
Result: Computes RF Link Budget & Fade Margin via EIRP = P_tx_dBm + G_tx_dBi − L_cable_dB; RSL = EIRP − PathLoss_dB + G_rx_dBi; FadeMargin = RSL − RxSensitivity.

Frequently Asked Questions

How does the RF Link Budget, EIRP, Received Signal Strength (RSSI dBm) & Fade Margin Calculator calculate results?

It evaluates EIRP = P_tx_dBm + G_tx_dBi − L_cable_dB; RSL = EIRP − PathLoss_dB + G_rx_dBi; FadeMargin = RSL − RxSensitivity directly in your browser and updates three custom SVG visualizations in real time.

Can I use Goal Seek to solve backwards for a required dimension or rating?

Yes. Click "🎯 Goal Seek" in the results toolbar to solve backwards for any numeric input parameter.

Does this engineering calculator work offline?

Yes. All calculations run 100% locally in your browser and work offline via the CalculatorGraph PWA.

Science & Engineering · RF, Telecom & Antenna Engineering

RF Link Budget, EIRP, Received Signal Strength (RSSI dBm) & Fade Margin Calculator: inputs, method, and how to read the result

Compute EIRP (dBm), Received Signal Level (dBm), and Fade Margin (dB) over any wireless link.

Choose inputs for the case you are checking

The defaults are illustrative. Replace them with values for your case and keep the units shown beside each field.

  • Tx Output Power Dbm: Transmitter power in dBm (20 dBm = 100 mW, 30 dBm = 1 W).
  • Combined Antenna Gain Dbi: Sum of Tx antenna gain + Rx antenna gain minus coax/connector loss (dB).
  • Total Path Loss Db: Free-space + atmospheric/clutter path loss (dB).
  • Rx Sensitivity Threshold Dbm: Receiver minimum sensitivity threshold for target BER (dBm).

What the calculation includes

With the default values shown, Received Signal Level (RSL / RSSI) is -71 dBm. The calculation follows RF Link Budget & Fade Margin Formula; the formula and variable definitions above show how the inputs combine.

One-input check: With the other defaults held constant, changing Tx Output Power Dbm from 23 dBm to 25 dBm changes Received Signal Level (RSL / RSSI) from -71 dBm to -69 dBm. This is a comparison inside the calculator's stated model, not a prediction.

Where to use caution

  • Uses standard NREL, IEEE, ASHRAE, and IRC design equations.
  • Verify final structural, electrical, and mechanical specifications against local building codes.

Scope: Global Engineering & Building Code Standard Check the assumptions and limitations against your situation before relying on the estimate.

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