<prompt> Human: When I do out my tax return for the two jobs I held in 2015 separately, I get back a large chunk of money for each. When I do them together on one tax form, it either tells me I owe money, or only get back 160.More specifically. I held one Job all of January through the September 1st. I get back lets say 1800 for that job when put into either TurboTax or HR Blocks refund service. Once I add my second job September through the end of the year, which alone says I should get back roughly 1500, TurboTax tells me I owe 140 dollars, and HR Block tells me I only get back 160 dollars. Why am I being penalized with my two jobs when I should be getting back roughly 3k? This is before going onto other deductions or anything else. Also my pay deductions were the same for both jobs and nothing changed other than health insurance between jobs.Thanks for any advise!Edit 1 - Clarification:I held each job through their own separate time periods. First job from January 1st - September 1st. Second job from September 2nd - end of year. Also both jobs had me in the same tax bracket so taxes would be at the same rate for both jobs. Pay difference was only 2k.Assistant: You are not penalized for having multiple jobs. Each job withholds assuming you have no other job. So, when you have multiple jobs, your total withholding across both jobs is less than it would have been if youd made all that income at a single job.Human: I held each job through their own separate time periods as mentioned. First job from January 1st - September 1st. Second job from September 2nd - end of year. Also both jobs had me in the same tax bracket so taxes would be at the same rate for both jobs. Pay difference was only 2k.Assistant: Lets say you make 50k in a year. You make 30k at your first job, then quit and go to a second job, where you make 20k for the rest of the year. Each job withholds taxes at the estimated effective rate of each of those income levels. If you only made 20kyear or 30kyear, then your effective tax rate is lower than if you make 50kyear, so the payroll software computes a lower deduction percentage per paycheck than if it knew you were making 50kyear total.Youll pay tax on your total income of 50k. This is the same amount of tax that youd owe if you made all 50k at a single job. However, the amount of taxes you had withheld throughout the year was lower than it would have been otherwise, due to each companies payroll software estimating your withholdings at a lower income level. So, since your withholding was lower than you otherwise expected, youll get less of a refund than you expected or owe more money than you expected, etc.Human: Great reply!Thanks for the detailed answer. Unfortunately I dont think that is it. My pay did not change at either job over time, or the amount of taxes held per paycheck. So this would make sense only if I paid more towards taxes in different parts of the year or after different durations with each company, but that was not the case. Being the static tax payments as they were, that would strongly suggest nothing else would have changed. So point being for both companies I was paid x, and paid y in taxes, and for both companies that ratio individually gave back a large refund. When the two companies are together, my refund is slashed with little evidence as to why.Also for the record, both companies were paying me within 2k of each other, within the same tax bracket as well, and worked at separate times in the year, never simultaneously. Just in case you didnt see the update.Assistant: Even if both companies withheld assuming your total annual rate, youll still run into this. When you only enter one of your W-2s into your tax software, it calculates your total income at 20k or 30k using my example instead of 50k, and until you enter the other W-2 it thinks your effective tax rate is lower since it thinks your income is lower. Thats normal. The lower amount is not your income, so the estimated refundowed amount isnt meaningful until youve entered all of your tax statements.Human: Still makes zero sense friend, and I do thank you for your efforts. However what youre telling me is that 50k in wages plus the x amount in taxes a large refund as one job, but a small refund as two jobs? Thats literally the exact situation Im in. To elaborate, both jobs taxed me assuming I would make my annual salary, lets say 60k, and between the two jobs I made exactly that.  <response>: However what youre telling me is that 50k in wages plus the x amount in taxes a large refund as one job, but a small refund as two jobs?No; if you make 50k at one job, or 50k total across two jobs, your federal tax liability is the same. However, when you only enter a single one of your W-2s into your tax software, the initial refundowed estimate is only based on partial information; your tentative effective tax rate isnt accurate because your standard deduction and personal exemption only apply once, and additional income stacks and spills over into higher tax brackets.Im going to try and use a very simplified example with made up numbers: Lets say theres only one tax bracket at 25, and your standard deductionpersonal exemption are 10,000 so the first 10k you make is taxed at 0. In this example, you made 50k total, or 40k taxable income, which results in 10k total taxes owed 40k 25 10k. Lets assume both your employers payroll software is exactly perfect; your 30k job withheld 6k for taxes and your 20k job withheld 4k for taxes.If you enter only the 30k W-2, your tax software only sees that amount of income, and calculates your taxes owed as 30k - 10k 25 20k 25 5k. You have a tentative refund of 6k withheld - 5k tax 1k.If you enter only the 20k W-2, your tax software only sees that amount of income, and calculates your taxes owed as 20k - 10k 25 10k 25 2.5k. You have a tentative refund of 4k withheld - 2.5k tax 1.5k.If you enter both of your W-2s, your tax software sees your total income of 50k, and calculates your taxes owed as 50k - 10k 25 40k 25 10k. Your have an actual refund of 0 10k withheld - 10k tax.In other words, the lower your income, in general the lower your effective tax rate the actual final of your income you pay in tax. Your tax software cant provide you with an accurate calculation until you enter all of your information. 