Attached document demonstrates calculations involved for a SEPIC converter. Calculations are based on “AN-1484 Designing A SEPIC Converter” by Dongbing Zhang from Texas Instruments.
If you are unable to view above PDF then here is the link to download the PDF: sepic-converter-calculations-for-fixed-output-voltage.pdf.
I prepared above document using Jupyter Notebook then converted to PDF using LaTex. Here is the Jupyter Notebook source file: sepic-converter-calculations-for-fixed-output-voltage.zip.