Hired with W-9, will I owe estimated tax quarterly?
You must pay your taxes at the quarterly intervals. For most people the withholding done by their employer satisfies this requirement. However, if your income does not have any withholding (or sufficient), then you must file quarterly estimated tax payments.  Note that if you have a second job that does withhold, then you can adjust your W4 to request further withholding there and possibly reduce the need for estimated payments.  Estimated tax payments also come into play with large investment earnings. The amount that you need to prepay the IRS is impacted by the safe harbor rule, which I am sure others will provide the exact details on.
"It's likely you don't have to make estimated tax payments if this is your first year of contracting (extra income), and your existing salary is already having taxes withheld. If you look at the 1040-ES: General Rule In most cases, you must pay estimated tax for 2014 if both  of the   following apply. This is easier to understand if you look at the worksheet.  Look at line 14b/14c and the associated instructions.  14b is your required annual payment based on last year's tax.  14c is the lesser of that number and 14a, so 14b is your ""worst case"".  14c is the amount of tax you need to prepay (withholding counts as prepayment). I'm going to apply this to your situation based on my understanding, because it's not easy to parse:" It will usually take a week or two for changes to your withholding to take effect in payroll.  However 0 deductions will withhold more per check than 3.  So if at 0 deductions you are having to pay in April then I would suggest not changing your W2 to 3 deductions.  Instead in the section for extra with holding add $25 per week.  This should leave you with a more manageable return in April. If you have non-salary income, you might be required to file 1040ES estimated tax for the next year on a quarterly basis. You can instead pay some or all in advance from your previous year's refund. In theory, you lose the interest you might have made by holding that money for a few months. In practice it might be worth it to avoid needing to send forms and checks every quarter. For instance if you had a $1000 estimated tax requirement and the alternative was to get 1% taxable savings account interest for six months, you'd make about $3 from holding it for the year. I would choose to just pay in advance. If you had a very large estimation, or you could pay off a high-rate debt and get a different effective rate of return, the tradeoff may be different. Most countries with income tax, including the USA, design their withholding system so that in straightforward cases, tax is withheld from each month's paycheck on an annualized basis: tax for a month is calculated on the assumption that you will keep earning the same monthly amount for the rest of the year, and the withholding is set so that the tax is spread evenly across the year. Another way of putting that is that in practice you only get the tax brackets allocated proportionately throughout the year - so up till the end of August you'll only have been assigned 8/12 of the $37450 bracket, and so on. So if your income doesn't change and your general tax affairs don't change, your paycheck also shouldn't change. If your income is irregular or changes during the year then things can get more complicated. As other answers have noted, withholdings are calculated according to tables that normally just take into account that specific month's income. There are various possible changes to your tax affairs that might cause the withholdings to change. For example there'd be an impact from any change in your contributions to tax advantaged things like health insurance or retirement, health or education savings. You might also use form W-4 to change your withholdings yourself. Note that even with a regular income that doesn't change through the year, you might find yourself either owing money or being owed a refund when you file your taxes after the end of the year. It's worth making sure that your W-4 accurately records the allowances you are entitled to, to minimize or eliminate this adjustment. Ultimately, you are the one that is responsible for your tax filings and your payments (It's all linked to your SSN, after all). If this fee/interest is the result of a filing error, and you went through a preparing company which assumes liability for their own errors, then you should speak to them. They will likely correct this and pay the fees.  On the other hand, if this is the result of not making quarterly payments, then you are responsible for it. (Source: Comptroller of Maryland Site) If you [...] do not have Maryland income taxes withheld by an employer, you can make quarterly estimated tax payments as part of a pay-as-you-go plan. If your employer does withhold Maryland taxes from your pay, you may still be required to make quarterly estimated income tax payments if you develop a tax liability that exceeds the amount withheld by your employer by more than $500. From this watered-down public-facing resource, it seems like you'll get hit with fees for not making quarterly payments if your tax liability exceeds $500 beyond what is withheld (currently: $0). "Your employer can require a W8-BEN or W-9 if you are a contractor, and in some special cases.  I believe this bank managing your stock options can as well; it's to prove you don't have ""foreign status"".  See the IRS's W-9 instructions for details." Your recruiter is likely trying to avoid having to pay the employer's side of employment taxes, and may even be trying to avoid having to file a 1099 for you by treating your relationship as a vendor/service provider that he is purchasing services from, which would make your pay just a business expense. It's definitely in his best interest for you to do it this way. Whether it's in your best interest is up to you. You should consult a licensed legal/tax professional to help you determine whether this is a good arrangement for you. (Most of the time, when someone starts playing tax avoidance games, they eventually get stung by it.) The next big question: If you already know this guy is a snake, why are you still working with him? If you don't trust him, why would you take legal/tax advice from him? He might land you a high-paying job. But he also might cause you years of headaches if his tax advice turns out to be flawed. Do you have a regular job, where you work for somebody else and they pay you a salary? If so, they should be deducting estimated taxes from your paychecks and sending them in to the government. How much they deduct depends on your salary and what you put down on your W-4. Assuming you filled that out accurately, they will withhold an amount that should closely match the taxes you would owe if you took the standard deduction, have no income besides this job, and no unusual deductions. If that's the case, come next April 15 you will probably get a small refund. If you own a small business or are an independent contractor, then you have to estimate the taxes you will owe and make quarterly payments. If you're worried that the amount they're withholding doesn't sound right, then as GradeEhBacon says, get a copy of last year's tax forms (or this year's if they're out by now) -- paper or electronic -- fill them out by estimating what your total income will be for the year, etc, and see what the tax comes out to be. Don't overthink it. As an employee, whether of your own corporation or of someone else, you get a salary and there are deductions taken out. As the owner of a business you get (hopefully) business profits as well. And, in general, you often have other sources of income from investments, etc. Your estimated tax payments are based on the difference between what was withheld from your salary and what you will owe, based on salary, business income, and other sources. So, in essence, you just add up all the income you expect, estimate what the tax bill will be, and subtract what's been withheld. That's your estimated tax payment. "I would suggest you pay quarterly. Or, if you prefer, do the extra withholding. Don't wait until the end of the year. My experience is that of having a day job with freelance work on the side. I've spent a few years just freelancing, and I paid quarterly as requested to avoid the penalties. Now that I have a good day job again, my freelancing is just a small part of my income, and so I end up with a net return and no longer have to pay quarterly. You shouldn't wait until the end of the year to pay. This is assuming your wife is bringing in a decent income. The only scenario where you would want to wait is if her income is only a small amount (such as my wife's plans for an Etsy store). To the IRS, it doesn't really make a difference whether you withhold extra or pay quarterly. Of those two choices, my preference is to pay quarterly - it's easy to set up calendar reminders on the quarterly payment dates, which are always the same. I did the same as bstpierre when estimating my payments: just take last year's tax (for the business) and divide by 4 (adjusting for any obvious situational differences). That's usually close enough. Paying quarterly instead of via withholding means you get to hold on to your money (on average) for 6 weeks longer. Granted, that doesn't mean much with today's interest rates, but it's something. You may prefer the simpler accounting for withholding, though - you can ""set and forget""." It is true that with a job that pays you via payroll check that will result in a W-2 because you are an employee, the threshold that you are worried about before you have to file is in the thousands. Unless of course you make a lot of money from bank interest or you have income tax withheld and you want it refunded to you. Table 2 and table 3 in IRS pub 501, does a great job of telling you when you must.  For you table 3 is most likely to apply because you weren't an employee and you will not be getting a W-2. If any of the five conditions listed below applied to you for 2016, you must file a return. You owe any special taxes, including any of the following. a. Alternative minimum tax. (See Form 6251.)    b. Additional tax on a   qualified plan, including an individual retirement arrangement (IRA),   or other tax­favored account.  (See Pub. 590­A, Contributions to   Individual Retirement Arrangements (IRAs); Pub. 590­B, Distributions   from  Individual Retirement Arrangements (IRAs); and Pub. 969, Health   Savings Accounts and Other Tax­Favored Health  Plans.) But if you are   filing a return only because you owe this tax, you can file Form 5329   by itself.   c. Social security or Medicare tax on tips you didn't   report to your employer (see Pub. 531, Reporting Tip Income) or on    wages you received from an employer who didn't withhold these taxes   (see Form 8919).    d. Write­in taxes, including uncollected social   security, Medicare, or railroad retirement tax on tips you reported to   your  employer or on group­term life insurance and additional taxes on   health savings accounts. (See Pub. 531, Pub. 969,  and the Form 1040   instructions for line 62.)   e. Household employment taxes. But if you   are filing a return only because you owe these taxes, you can file    Schedule H (Form 1040) by itself. f. Recapture taxes. (See the Form   1040 instructions for lines 44, 60b, and 62.) You (or your spouse if filing jointly) received Archer MSA, Medicare Advantage MSA, or health savings account  distributions. You had net earnings from self­employment of at least $400. (See Schedule SE (Form 1040) and its instructions.) You had wages of $108.28 or more from a church or qualified church­controlled organization that is exempt from employer  social   security and Medicare taxes. (See Schedule SE (Form 1040) and its   instructions.) Advance payments of the premium tax credit were made for you, your spouse, or a dependent who enrolled in coverage  through the Health   Insurance Marketplace. You should have received Form(s) 1095­A showing   the amount of the advance  payments, if any. It appears that item 3: You had net earnings from self­employment of at least $400. (See Schedule SE (Form 1040) and its instructions.) would most likely apply. It obviously is not too late to file for 2016, because taxes aren't due for another month. As to previous years that would depend if you made money those years, and how much. You will not necessarily incur a penalty.  You can potentially use the Annualized Income Installment method, which allows you to compute the tax due for each quarter based on income actually earned up to that point in the year.  See Publication 505, in particular Worksheet 2-9.  Form 2210 is also relevant as that is the form you will use when actually calculating whether you owe a penalty after the year is over. On my reading of Form 2210, if you had literally zero income during the first quarter, you won't be expected to make an estimated tax payment for that quarter (as long as you properly follow the Annualized Income Installment method for future quarters).  However, you should go through the calculations yourself to see what the situation is with your actual numbers. I am surprised no one has mentioned the two biggest things (in my opinion).  Or I should say, the two biggest things to me.  First, 1099 have to file quarterly self employment taxes.  I do not know for certain but I have heard that often times you will end up paying more this way then even a W-2 employees.  Second, an LLC allows you to deduct business expenses off the top prior to determining what you pay in taxes as pass-through income.  With 1099 you pay the same taxes regardless of your business expenses unless they are specifically allowed as a 1099 contractor (which most are not I believe).  So what you should really do is figure out the expense you incur as a result of doing your business and check with an accountant to see if those expenses would be deductible in an LLC and if it offsets a decent amount of your income to see if it would be worth it.  But I have read a lot of books and listened to a lot of interviews about wealthy people and most deal in companies not contracts.  Most would open a new business and add clients rather than dealing in 1099 contracts.  Just my two cents... Good luck and much prosperity. Welcome to the wonderful but oft confusing world of self-employment. Your regular job will withhold income for you and give you a W2, which tells you and the government how much is withheld.  At the end of the year uber will give you and the government a 1099-misc, which will tell you how much they paid you, but nothing will be withheld, which means you will owe the government some taxes. When it comes to taxes, you will file a 1040 (the big one, not a 1040EZ nor 1040A).  In addition you will file a schedule C (self-employed income), where you will report the gross paid to you, deduct your expenses, and come up with your profit, which will be taxable.  That profit goes into a line in the 1040.   You need to file schedule SE.  This says how much self-employment tax you will pay on your 1099 income, and it will be more than you expect.  Self employment tax is SS/Medicare.  There's a line for this on the 1040 as well.  You can also deduct half of your self-employment tax on the 1040, there's a line for it. Now, you can pay quarterly taxes on your 1099 income by filing 1040-ES.  That avoids a penalty (which usually isn't that large) for not withholding enough.  As an alternative, you can have your regular W2 job withhold extra.  As long as you don't owe a bunch at tax time, you won't be a fined. When you are self-employed your taxes aren't as simple.  Sorry.  You can either spend some time becoming an expert by studying the instructions for the 1040, pay for the expensive version of tax programs, or hire someone to do it for you. Self-employed taxes are painful, but take advantage of the upsides as well.  You can start a solo 401(k) or SEP IRA, for example.  Make sure you are careful to deduct every relevant business expense and keep good records in case you get audited. The I-9 form is required because you are working. It is kept by the employer as proof that you have the proper documents to work. If the government was to inspect their records they can be fined if they don't have those document, in fact they have to keep them for several years after your employment is done. A w-4 form is a federal tax form. There also was probably a state version of the form.  When you completed the w-4 it is used by your employer to determine how much in taxes need to be withheld. Employers don't know your tax situation. Even though you are on work study, you still could have made enough money over the summer to pay taxes. But if this is your only job, and you will not make enough money to have to pay taxes, you can fill out the form as exempt. That means that last year you didn't make enough money to have to pay taxes, and you don't expect to make enough to have to pay taxes this year. If you are exempt, no federal income tax will be withheld. They might still withhold for social security and medicare. The state w-4 can also be used to be exempt from state taxes. If they withhold any income taxes you have to file one of the 1040 tax forms to get that income tax money back. You will have to do so for the state income tax withholding.  A note about social security and medicare. If you have an on campus job, at the campus you attend, during the school year; they don't withhold money for social security and medicare. That law applies to students on work study jobs, and on non-work-study jobs. for single dependents the federal threshold where you must file is: > You must file a return if any of the following apply. Your gross income was more than the larger of— a. $1,000, or b. Your earned income (up to $5,850) plus $350.