I forgot to pay last three quarters of estimated taxes amounting to $6000. What will be neater to send IRS last three coupons along with $2000 each or just send IRS the last coupons with a $6000 check. I guess by default, IRS will average the outstanding estimated amounts across quarters anyway.
When I did calculations it came with a penalty of like $300, if I do nothing and pay all on 15th with my annual return.
What the best way to do it without raising any red flags.