There is no definitive percentage. We don't even know for sure if "percentage of current loan paid back" is actually part of the criteria they use to decide when to offer you another loan. Assuming it is though, the percentage would likely be different for everyone based on each account's particular metrics.

Precisely what needs to be done to get a new loan offer is never going to be revealed, as it is proprietary information. All that can be recommended is to keep processing cards, keep working on improving all of your metrics, and perhaps one day you'll be blessed with the pleasant surprise of a loan offer.

I recommend that you never expect a Square Capital loan. Never plan to be getting one. Never hope to get one. Sorry to say, the only way to deal with Square Capital without setting yourself up for frustration is to behave as if the Capital program doesn't even exist, and view any Capital loan that does show up as a nice surprise.

Counting on them isn't recommended. Lots of tears shed on this forum from people who have.