I've been highly compensated for a while now, and I have never used a tax professional. My past complications include the year that my company was bought by a VC firm and my stock options and stock held were bought out to the tune of 5x my salary. And now I have two kids in college, with scholarships, and paying the remainder out of 529 accounts.
Usually, I don't even use tax software. My typical method is to use the online software -- like turbotax online -- and let it figure out where I am. Then I use the "Free File Fillable forms" online to actually complete the process. Search for "Free File Fillable Forms" -- it's not the same as using turbotax or TaxAct for free.
My suggestion to you: download the PDF form of 1040EZ and 1040A from the IRS. Print the EZ, and fill it out. This will give you a better feel for what exactly is going on. With your income, I don't think you can file the EZ, but it's a good way to get your feet wet.
The way income taxes work here in the US:
- some of your income is not taxable. For example, if you pay for health insurance through your employer, or make 401k contributions, that premium is typically excluded from your income for purposes of computing income taxes
- After making some additions (like bank interest, stock dividends) and subtractions (like for IRA contributions), the form tells you your "Adjusted Gross Income".
- Then other income is excluded. There's the "Personal Exemption" (one per family member if you're not single), and the "Standard Deduction". If you own a home or contribute a lot to charity and churches, it might be better to itemize deductions than take the standard deduction.
According to the IRS, the Personal Exemption this year is worth $4,050, and the Standard Deduction $6,300, assuming you're single.
Lets assume that your salary will be in fact 75,000, and you don't pay for any benefits, but you do make a 401k contribution of 15% of your salary. Then your W-2 at the end of the year should tell you to put 63,750 in a particular box on your 1040 form. (63,750 is 85% of 75,000). Lets then assume 63,750 is your AGI after other additions and subtractions. 63,750 - 4,050 - 6,300 == 53,400.
The federal Tax system is graduated, meaning there are different ranges (brackets) with different percentages. The term tax people use for taxable income of 53,400 is "marginal tax rate"...so the last dollar they tax at 25%. Other dollars less. According to the IRS, if you're single, then on 53,400, you pay "$6,897.50 plus 25% of the amount over $50,400" Or 6897.50 + 750, or 7647.50.
Note this is only Federal Income Tax. You will also be paying Social Security and Medicare payroll Tax. And I'm guessing you'll also be paying colorado state income tax. Each state has its own forms and methods for figuring out the taxes and stuff.
By the way, when you start, you'll fill out a "W-4" form to "help" you figure out how much to withhold from every paycheck. (I find the W-4 is not helpful at all). Your company will withhold from your paycheck some mysterious amount, and the process of filling out your 1040A or 1040EZ or whatever will be, likely, to get the over-withheld amount back.