How is loss-limited fiber distance calculated?

Subtract connection, splice, passive-device, and engineering-reserve losses from the equipment power budget. Divide the remaining fiber-loss allowance by the selected attenuation coefficient in decibels per kilometer.

Which transmitter value should I enter?

Use the minimum transmitter output guaranteed by the equipment specification. The low-power case governs maximum attenuation and receiver-sensitivity margin.

Why can the published equipment reach be shorter than the calculated distance?

An attenuation budget does not by itself evaluate protocol limits, modal bandwidth, chromatic dispersion, optical path penalties, launch conditions, or other application requirements. Enter the published reach limit so the shorter value governs.

Does this calculator replace a complete optical link budget?

No. It solves a maximum distance from the low-power attenuation budget. Use Link Budget to verify a selected route and the complete receiver operating window, including overload when applicable.

Fiber Optic Maximum Distance Calculator — Loss-Limited Reach

Project details (optional)Add details

Project / jobLocationPrepared byField notes

How to use this calculator

Enter the minimum transmitter output and receiver sensitivity from the same equipment specification.
Count every mated connection, splice, splitter, WDM, and other fixed loss in the selected optical path.
Select the fiber profile and reserve. Add an optional equipment or application reach limit when one is published.
Use the shorter governing distance, then verify it in the complete Link Budget workflow.

Step 1 · Equipment

Enter the low-power operating limits

Minimum transmitter output — dBmUse the lower value in the published TX range.Receiver sensitivity — dBmUse the minimum acceptable receiver input and preserve its sign.

Both values are required because their difference is the equipment power budget. Do not enter receiver overload here; use Link Budget for the full minimum/maximum operating-window check.

Fiber Maximum Distance Report

REVIEW INPUT

Report date: 8/22/2026
Calculation scope: Loss-limited maximum distance

Engineering use

Verify equipment reach, wavelength, fiber specification, dispersion and bandwidth limits, all passive losses, reserve, and the complete receiver operating window before design acceptance.

Report incomplete

Minimum transmitter output is required.

Enter the low-power operating limits

Report incomplete

Related calculators