If I remember correctly, the penalty for not paying your estimated quarterlies (or underpaying them) is ~3%.
Tell me where you can get a business loan with a 3% interest rate :evil_laughter:
If you're a bank, The Fed! :uhoh2:
Also if you are going to make more this year, if you just pay what you did last year there is no penalty for the unpaid balance.
Also I think there is like a 10% buffer of error built in to it as well. So if you paid 8% less than you where suppose to, no penalty.