I was under the impression that as long as a specific amount was in before DEC 31, you're ok. The amount is XX??% of the tax you paid last year, unless this year's tax is less. That percentage might be 85%, but I may be totally wrong.
I got the following information
from the IRS website.
You’re supposed to pay estimated taxes if you expect to owe tax of $1,000 or more when you file your return.
You won’t get a penalty for not paying the estimated tax if:
You paid at least 90% of the tax owed OR 100% of the amount of the tax for the prior year.
(The deadlines for the estimated payments are 15 days after the close of the quarter. Or they can give you a penalty.)
avrumy - I hope you don't get a penalty. Good luck.