Estimated Taxes after surge in income
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. "Well a definitive answer would require a lot of information.  Instead of posting that kind of info online, you should take a look at the instructions for Form 2210 and in particular ""Schedule AI -- Annualized Income Installment Method,"" which corrects the penalty for highly variable income.   Using this form you will likely be able to avoid the penalty, but it is hard to know for sure."
"You are not interpreting the table correctly. The $20K ""base rate"" that you think should have been eliminated is in fact the total tax for the whole bracket. You only dipped partially into the bracket, and the $3K reduction accounts for that. Look at the table again: What it means is that if you earn $100K, you will pay $6897.50 + 25% of (100000-50400) = $12400. If you earn $140000, you'll pay $26835 + (140000-130150) * 0.28 = $2758. So why the difference between $26835 and $6897.50? That's exactly 25% of $79500, which is the difference between $130150 and $50400 - the whole value of the bracket." My understanding (I've never filed one myself) is that the 1040ES is intended to allow you to file quarterly and report unpredictable income, and to pay estimated taxes on that income.   I was in the same sort of boat for 2016 -- I had a big unexpected income source in 2015, and this took away my Safe Harbor for 2016.  I adjusted my w-2 to zero exemptions (eventually) and will be getting a refund of about 1% of our income. So lets say you make 10000 in STG in March, and another 15000 in STG in April.  File a quarterly 1040-ES between March 31 and April 15.  Report the income, and pay some tax.  You should be able to calculate the STCG Tax for 10k pretty easily.  Just assume that it comes off the top and doesn't add at all to your deductions.  Then for April, do the same by June 15. Just like your W-2 is used to estimate how much your employer should withhold, the 1040ES is designed to estimate how much extra you need to pay to the IRS to avoid penalties.  It'll all get resolved after you file your final 1040 for the 2017 calendar year. Since your YouTube income is considered self-employment income and because you probably already made more than $400 in net income (after deducting expenses from the $4000 you've received so far), you will have to pay self-employment tax and file a return.  This is according to the IRS's Publication 17 (2016), Your Federal Income Tax, so assumes the same rules for 2016 will remain in effect for 2017: You are self-employed if you: Carry on a trade or business as a sole proprietor, Are an independent contractor, Are a member of a partnership, or Are in business for yourself in any other way. Self-employment can include work in addition to your regular full-time business activities, such as certain part-time work you do at home or in addition to your regular job. You must file a return if your gross income is at least as much as the filing requirement amount for your filing status and age (shown in Table 1-1). Also, you must file Form 1040 and Schedule SE (Form 1040), Self-Employment Tax, if: Your net earnings from self-employment (excluding church employee income) were $400 or more, or You had church employee income of $108.28 or more. (See Table 1-3.) Use Schedule SE (Form 1040) to figure your self-employment tax. Self-employment tax is comparable to the social security and Medicare tax withheld from an employee's wages. For more information about this tax, see Pub. 334, Tax Guide for Small Business. I'd also note that your predicted income is getting close to the level where you would need to pay Estimated Taxes, which for self-employed people work like the withholding taxes employers remove their employees paychecks and pay to the government. If you end up owing more than $1000 when you file your return you could be assessed penalties for not paying the Estimated Taxes. There is a grace period if you had to pay no taxes in the previous year (2016 in this case), that could let you escape those penalties. The safe harbor provision is based on the tax you or the prior year. So in 2016 this helped you as your tax was substantially increased from 2015. However, by the same token in 2017 your safe harbor amount is going to be very high. Therefore if 2017 is similar you will owe penalties. The solution here is to make estimated tax payments in the quarters that you realize large gains. This is exactly what the estimated tax payments are for. Your estimate tax payments do not have to be the same. In fact if you have a sudden boost in earnings in quarter 3, then the IRS expects that quarter 3 estimated tax payment to be boosted. When you adjust your investments the following will happen: Initial condition: Modified condition: This means that after this change you will note that the amount of federal tax you pay each month via withholding will go up. You are now contributing less pre-tax, so your taxable income has increased. If you make no other changes, then in April you will either have increased your refund by 6 months x the additional $25 a month, or decreased the amount you owe by the same amount. There is no change in the total 401K balance at the end of the year, other than accounting for how much is held pre-tax vs. Roth post-tax. Keep in mind that employer contributions must be pre-tax. The company could never guess what your tax situation is. They withhold money for taxes based on the form you fill out, but they have no idea of your family's tax situation. If you fail to have enough withheld, you pay the penalty — not the company. *The tax savings are complex because it depends on marital status, your other pre-tax amounts for medical, and how much income your spouse makes, plus your other income and deductions. Earned income is earned income.  You can put your bonus in a tax-advantaged account, or not, just like you can put your salary in a tax-advantaged account, or not.  If you don't, it's taxed as ordinary income. Now, it may look like they're taking a ton out of your paycheck, but part of what may be happening is that, for that paycheck, it looks like you're making a whole lot more, so they're withholding a whole lot more based on a probably conservative formula that will make sure you (and they) don't get in trouble with the IRS for underwithholding.  So, if they're taking out too much with this paycheck, you'll get it back when you file your taxes.  Or, you can change your withholding yourself to account for this. First, I'd use an online tax calculator to figure out you total tax tab for the year. Then look through Circular E and figure out from there how much tax you should pay for the rest of the year and work backwards to calculate the number of allowances to get there.  Two friendly warnings - Since you are doing this midyear, you'll need to repeat this exercise as we go into 2017. These next 6 months, you'll be withholding less than normal to make up for the high holdings so far. Second, a withholding is like saying tax/don't tax me on $4050. So in the 25% bracket, it's +/- $1000 in tax paid. You can adjust closer via the line 6 on W4 'additional withholding'. "There are way too many details missing to be able to give you an accurate answer, and it would be too localized in terms of time & location anyway -- the rules change every year, and your local taxes make the answer useless to other people. Instead, here's how to figure out the answer for yourself. Use a tax estimate calculator to get a ballpark figure. (And keep in mind that these only provide estimates, because there are still a lot of variables that are only considered when you're actually filling out your real tax return.) There are a number of calculators if you search for something like ""tax estimator calculator"", some are more sophisticated than others. (Fair warning: I used several of these and they told me a range of $2k - $25k worth of taxes owed for a situation like yours.) Here's an estimator from TurboTax -- it's handy because it lets you enter business income. When I plug in $140K ($70 * 40 hours * 50 weeks) for business income in 2010, married filing jointly, no spouse income, and 4 dependents, I get $30K owed in federal taxes. (That doesn't include local taxes, any itemized deductions you might be eligible for, IRA deductions, etc. You may also be able to claim some expenses as business deductions that will reduce your taxable business income.) So you'd net $110K after taxes, or about $55/hour ($110k / 50 / 40). Of course, you could get an answer from the calculator, and Congress could change the rules midway through the year -- you might come out better or worse, depending on the nature of the rule changes... that's why I stress that it's an estimate. If you take the job, don't forget to make estimated tax payments! Edit: (some additional info) If you plan on doing this on an ongoing basis (i.e. you are going into business as a contractor for this line of work), there are some tax shelters that you can take advantage of. Most of these won't be worth doing if you are only going to be doing contract work for a short period of time (1-2 years). These may or may not all be applicable to you. And do your research into these areas before diving in, I'm just scratching the surface in the notes below." Your tax return will be due on April 18th of 2017 for the amounts made in 2016. Based on the figures that you have provided, assuming you are 18, and assuming you are a single taxpayer your total tax will be around $2600.00 ($2611.25 to be exact, without additional credits or deductions to AGI accounted for). The $1,234 in fed. inc. tax that you have already paid is considered to be a prepaid by the government. If at year-end you have provided more than you have made the government will refund you the excess (federal tax return). The answer to this question requires looking at the mathematics of the Qualified Dividends and Capital Gains Worksheet (QDCGW). Start with Taxable Income which is the number that appears on Line 43 of Form 1040.  This is after the Adjusted Gross Income has been reduced by the Standard Deduction or Itemized Deductions as the case may be, as well as the exemptions claimed.   Then, subtract off the Qualified Dividends and the Net Long-Term Capital Gains (reduced by Net Short-Term  Capital Losses, if any) to get the non-cap-gains part of the Taxable Income. Assigning somewhat different meanings to the numbers in the OPs' question, let's say that the Taxable Income is $74K of which $10K is Long-Term Capital Gains leaving $64K as the the non-cap-gains taxable income on Line 7 of the QDCGW.   Since $64K is smaller than $72.5K (not $73.8K as stated by the OP) and this is a MFJ return, $72.5K - $64K = $8.5K of the long-term capital gains are taxed at 0%. The balance $1.5K is taxed at 15% giving $225 as the tax due on that part.   The 64K of non-cap-gains taxable income has a tax of $8711 if I am reading the Tax Tables correctly, and so the total tax due is $8711+225 = $8936.  This is as it should be; the non-gains income of $64K was assessed the tax due on it, $8.5K of the cap gains were taxed at 0%, and $1.5K at 15%. There are more complications to be worked out on the QDCGW for high earners who attract the 20% capital gains rate but those are not relevant here. You may be able to find the answers to your question on the IRS web site: http://www.irs.gov/businesses/small/article/0,,id=98263,00.html Specifically, using this form to estimate taxes for salary: http://www.irs.gov/pub/irs-pdf/f1120w.pdf and this form to estimate taxes for dividends: http://www.irs.gov/pub/irs-pdf/f1040es.pdf 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. "See Publication 505, specifically the section on ""Annualized Income Installment Method"", which says: If you do not receive your income evenly throughout the year (for example, your income from a repair shop you operate is much larger in the summer than it is during the rest of the year), your required estimated tax payment for one or more periods may be less than the amount figured using the regular installment method. The publication includes a worksheet and explanation of how to calculate the estimated tax due for each period when you have unequal income.  If you had no freelance income during a period, you shouldn't owe any estimated tax for that period. However, the process for calculating the estimated tax using this method is a good bit more complex and confusing than using the ""short"" method (in which you just estimate how much tax you will owe for the year and divide it into four equal pieces).  Therefore, in future years you might want to still use the equal-payments method if you can swing it.  (It's too late for this year since you missed the April deadline for the first payment.)  If you can estimate the total amount of freelance income you'll receive (even though you might not be able to estimate when you'll receive it), you can probably still use the simpler method.  If you really have no idea how much money you'll make over the year, you could either use the more complex computation, or you could use a very high estimate to ensure you pay enough tax, and you'll get a refund if you pay too much." "The heart of the question is: why can't Bill just pay whatever he owes based on his income in that quarter? If Q2 is gang busters, he'll increase his tax payment. Then if Q3 is surprisingly slow, he'll pay less than he paid in Q2. I think what's most interesting about this question is that the other answers are geared towards how a taxpayer is supposed to estimate taxes. But that's not my objective -- nor is it Bill's objective. My [his] real objective is:  In other words, the answer to this question either needs to deal with not overpaying, or it needs to deal with mitigating the underpayment penalty. AFAICT, there are 2 solutions: Solution 1 Figure your estimated taxes based on last year's tax. You won't owe a penalty if your withholding + estimated tax payments in each quarter are 25% or more of your previous year's tax liability. Here's the section that I am basing this on: http://www.irs.gov/publications/p505/ch04.html Minimum required each period.   You will owe a penalty for any 2011 payment period for which your estimated tax payment plus your withholding for the period and overpayments for previous periods was less than the smaller of: 22.5% of your 2011 tax, or 25% of your 2010 tax. (Your 2010 tax return must cover a 12-month period.) Solution 2 Use the ""Annualized Income Installment Method"". This is not a method for calculating estimated taxes, per se. It's actually a method for reducing or eliminating your underpayment penalty. It's also intended to assist tax payers with unpredictable incomes. If you did not receive your income evenly throughout the year (for example, your income from a shop you operated at a marina was much larger in the summer than it was during the rest of the year), you may be able to lower or eliminate your penalty by figuring your underpayment using the annualized income installment method. Emphasis added. In order to take advantage of this, you'll need to send in a Schedule AI at the end of the year along with a Form 2210. The downside to this is that you're basically racking up underpayment penalties throughout the year, then at the end of the year you're asking the IRS to rescind your penalty. The other risk is that you still pay estimated taxes on your Q2 - Q4 earnings in Q1, you just pay much less than 25%. So if you have a windfall later in the year, I think you could get burned on your Q1 underpayment." There are a few methods you can use to estimate your taxes. On the results screen, the app will show you your estimated tax burden, your estimated withholding for the year, and your estimated overpayment/refund or shortfall/tax due.  It may also have recommendations for you on how to adjust your W-4 (although, this late in the year, I think it only tells you to come back next year to reevaluate).   Your state might also have income tax, and if you are curious about that, you can find the state tax form and estimate your state income tax as well. My guess is that you will be getting a refund this year, as you have only worked half of the year.  But that is only a guess.