My wages double since last year. Not enough to change my tax bracket, and the amount of money taken out is about 3x as much as before. How is my refund about the same?

[TaxGuyBill]

Your Standard Deduction (and personal exemptions in 2017) did not double.

If you made $18,000 in 2017 and claimed a $10,000 for the Standard Deduction and personal exemption, your income subject to tax was $8,000.
If you made $36,000 in 2018 and claimed a $12,000 Standard Deduction (there are no personal exemptions in 2018), your income subject to tax is $24,000.  

In that example, even though your income doubled, the amount of income subject to tax (after the Standard Deduction) tripled.

Does that make sense?

[moorelo2018]

Yes. Thank you. Also, I have an old W-2 from 2016. I am still within the time frame to file for it. Should I file them together or separately?

[xmasbaby0]

You cannot add that 2016 W-2 into your 2018 return.  Each tax year has to be filed separately.

 If you need to prepare a return for 2015, 2016, or 2017 you can purchase and download desktop software to do it, then print, sign,  and mail the return(s)
<a rel="nofollow" target="_blank" href="https://turbotax.intuit.com/personal-taxes/past-years-products/">https://turbotax.intuit.com/persona...>
Remember to prepare your state return as well—if you live in a state that has a state income tax.
When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s.  Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS received the return.
Note:  The desktop software you need to prepare the prior year return must be installed/downloaded to a full PC or Mac.  It cannot be used on a mobile device.

[Bsch4477]

We can't see your return and a refund is the product of many variables.  Compare your returns side by side to try to see what changed.