just banking the money and owing at the end of the year also, kind of how we did it last year
That’s OK, but watch out for penalties, though.
You may owe penalties if you owe more than $1000.
You can avoid a penalty for underpayment of estimated taxes if you meet a “safe harbor” payment amount: the smaller of 90 percent of what is ultimately owed or a percentage of the taxes you paid in the previous year. If you make less than $150,000, the safe harbor is 100 percent of the previous year’s taxes. If you make more than $150,000, the prior-year safe harbor percentage is more than 100 percent.
IRS Pub 505 for details.
