This was helpful for me:
To illustrate, let's assume that Etan's net earnings from self-employment are $50,000 and he reasonably allocates 77%, or $38,500 to the deferral period. His maximum deferral amount is therefore $2,204 ($38,500 × 0.9235 × 0.062). Here, the 6.2% represents one-half of the social security portion (12.4%) of SE tax.
Found here https://www.thetaxinstitute.com/insights/tax-in-the-news/setax-deferral-cares-qotw/#:~:text=To%20ill....
