<prompt> Human: Im a SAHM and my husband works a regular job plus does some contract work on the side. He started this 1099 job in December and as of yesterday he has made 13,500 for Jan - April. As of the end of March, he has made 7,000. Do we need to file quarterly taxes even if his mainprimary income is from a regular job? What is the penalty if we dont? Can someone show me what forms we need to fill out and is it too late since we are already in April?Thank you in advance!  <response>: For 2015 taxes, the 1099 income he made in December will be part of the 2015 tax filing. Whereas his wages will go on 1040 line 7, hell use line 12 to report his contract work profit. Use a 2015 Schedule C-EZ or C to find his profit revenue minus deductible business expenses.Also, if he earned over 434 in self-employment in 2015, he should be paying SE taxes on it -- which support Social Security and Medicare. Use Schedule SE to find that amount and put it on 1040 line 57. You also get to deduct a number equal to 12 SE tax on 1040 line 27 before you calculate income taxes.---For 2016, do a projection of the 2016 total adjusted gross income using his W-2 job plus 1099 work, after the line 27 deduction you expect for 2016, and use this on 1040-ES worksheet line 1. Work through the worksheet to determine a good approximation of the 2016 tax liability. Then to find out how much to send in as estimated tax ... Calculate 90 of 2016 tax liability. Calculate 100 of 2015 tax liability 110 if higher income. Take the lesser of those two numbers. Subtract out your projection of the total workplace withholding that will happen in 2016. The result needs to be sent in via estimated payments, and you can divide it by 4 and make four equal estimated payments. Thats my paraphrase of some of the key steps in the 1040-ES booklet worksheet.Thats the way to avoid an underpayment penalty. Another method is to increase his withholding at W-2 job via filling out a new W-4 form at work. Sending in the additional taxes that way during the year works too.At tax time next April 2017, youll know the actual W-2 income, W-2 withholding, 1099 revenue, 1099 expenses, 1099 profit, SE tax related to that profit, and will calculate your actual 2016 tax liability. On the 2016 Form 1040, line 64 will show his W-2 withholding and line 65 will show the total estimated tax payments that you paid during the year and then youll be able to see if you still owe anything or if you get a refund. 