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Fibre Splice Loss Calculator

Work out fibre splice loss instantly with clear inputs, formula shown and shareable results.

About Fibre Splice Loss Calculator

Fusion splices typically add 0.1 dB or less, mechanical splices around 0.3 and field-terminated connectors up to 0.75, so splice technology has a large effect on a long route with many joints. Acceptance testing checks each splice individually rather than only the end-to-end loss, because one bad splice can be masked by a generous total budget.

Formula

Splice loss

expected total = splice count x typical loss per splice; worst case = count x worst measured splice

Worked example

With the default values below, Fibre Splice Loss Calculator returns Expected total splice loss of 0.80. Change any input above and every figure here is recalculated in your browser.

Inputs used

Number of splicesminimum 1
8
Splice typeone of Fusion splice (0.1 dB typical), Mechanical splice (0.3 dB typical), Field-terminated connector (0.75 dB)
Fusion splice (0.1 dB typical)
Worst measured spliceaccepts 0–3 dB
0.35 dB
Acceptance threshold per spliceaccepts 0.01–3 dB
0.3 dB

Results

Expected total splice loss
0.80 dB
Total if every splice matched the worst
2.80 dB
Typical loss per splice
0.10 dB
Acceptance test
Worst splice exceeds the acceptance threshold - re-splice it

Step by step

  1. 1Values used
  2. 2Splice loss
  3. 3Expected total splice loss= 0.80 dB
  4. 4Total if every splice matched the worst= 2.80 dB
  5. 5Typical loss per splice= 0.10 dB
  6. 6Acceptance test= Worst splice exceeds the acceptance threshold - re-splice it

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, fees or charges or compounding frequency 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 test each splice rather than end to end?

An OTDR trace localises loss. A link that passes end-to-end can hide a marginal splice that will fail as it ages or when the cable is disturbed.

What causes a high splice loss?

Core misalignment, contamination, a poor cleave angle, or mismatched fibre types. Cleaning and re-cleaving before re-splicing fixes most cases.

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