Fiber Field KitFree calculators for splicers, techs and fiber designers

About and sources

Fiber Field Kit is a set of free calculators and reference charts for the people who build and test fiber networks: splicers, OSP and FTTH techs, installers and designers. Every tool works on a phone, needs no account, and keeps working with no signal once you have opened it.

Who builds it

Fiber Field Kit is built and maintained by Fiber Optic Services 4U LLC, a fiber optic contractor in Milton, Pennsylvania. The company does fusion splicing, FTTH splitter and terminal work, OTDR testing and closeout, and aerial and underground construction. These are the calculations its crews do on the job, put where anyone in the trade can use them.

Why it exists

The numbers a tech needs on a job are scattered across vendor PDFs, store pages, scanned charts and spreadsheets that do not fit a phone screen. This site puts them in one place, shows the formula behind every result, and states where each default comes from so you can check it.

Where the numbers come from

  • Loss limits (fiber attenuation, connector and splice maximums) follow ANSI/TIA-568.3, the US structured cabling standard for optical fiber, as summarised by the Fiber Optic Association.
  • Color code follows ANSI/TIA-598, the color coding standard for fiber optic cable.
  • PON loss classes come from the ITU-T G.984 (GPON) and G.9807 (XGS-PON) recommendations.
  • Conduit fill uses the National Electrical Code, Chapter 9, Tables 1 and 4, and Article 770 for when those limits apply to optical cable.
  • Typical values (what a good splice or connector actually reads) are labelled as typical, not as limits, and come from manufacturer datasheets.

Standards change. Your project's spec, the cable manufacturer's sheet and the equipment datasheet always win over a general figure here.

Spotted a wrong number?

Email hello@fiberfieldkit.com with the page and the source that says otherwise. Corrections are made quickly and credited if you want.

How the site is paid for

The calculators are free and always will be. The site is supported by ads, which are kept away from the inputs and buttons so you will not tap one by accident.