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Fiber Optic Loss Budget Calculator

Calculate total fiber link loss from cable length, connectors, splices, and splitter losses. Includes safety margin for reliable link design.

Inputs

km
dB

Results

Total Link Loss

3.35 dB

Total + 3 dB Margin

6.35 dB

Cable Attenuation1.75 dB
Splice Loss0.2 dB
Connector Loss1.4 dB
Splitter Loss0 dB
Fiber Attenuation Rate0.35 dB/km
How to Use This Calculator
  1. Enter Cable Length (km) and select Fiber Type & Wavelength to set the attenuation rate (dB/km).
  2. Enter Number of Splices and Number of Connectors in the link.
  3. Add Splitter Loss (dB) if passive optical splitters are in the path (e.g., PON networks).
  4. Review Total Link Loss (dB) and Total + 3 dB Margin — the margin version is what you compare against your optical power budget.
  5. If Total + 3 dB Margin exceeds your transceiver's power budget, reduce link length, use fewer connectors, or upgrade to a higher-power transceiver.

How the result changes with Cable Length

Cable LengthTotal Link LossTotal + 3 dB Margin
208.6 dB11.6 dB
7026.1 dB29.1 dB
13047.1 dB50.1 dB
18064.6 dB67.6 dB

What each input means

Cable Length
Total fiber cable run length in kilometers
Fiber Type & Wavelength
1=Single-Mode 1310nm, 2=SM 1550nm, 3=Multi-Mode 850nm, 4=MM 1300nm
Number of Splices
Total fusion splices in the link (typical: 0.05 dB each for single-mode)
Number of Connectors
Total mated connector pairs (LC, SC, etc. — typical: 0.35 dB each)
Splitter Loss
Optical splitter insertion loss (for PON networks: 1:8 = 10.5 dB, 1:32 = 17.5 dB)

How this is calculated

Formula

Total Loss = (Length × dB/km) + (Splices × dB/splice) + (Connectors × dB/connector) + Splitter Loss

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Cable Length = 5, Fiber Type & Wavelength = 1, Number of Splices = 4, Number of Connectors = 4 = 5 input(s) provided
  2. Calculate Total Link Loss
    Total Link Loss
    3.35 = 3.35
  3. Calculate Total + 3 dB Margin
    Total + 3 dB Margin
    6.35 = 6.35
  4. Calculate Cable Attenuation
    Cable Attenuation
    1.75 = 1.75
  5. Calculate Splice Loss
    Splice Loss
    0.2 = 0.2

Engine last updated . Checked against 6 independently-derived tests — how we verify calculators.

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