The most common reasons people with income and expenses that are similar from 2017 to 2018 are different are
- When the new law was passed many employers lowered the employee withholdings to match the new tax laws. This means you may have seen a few extra dollars in your weekly paycheck. Compare box 2 of your W2 from last year to this year or line 17 on your 1040 this year to taxes withheld on your 1040 form from last year (the line will depend on your form)
- Itemized deductions are less due to changes in the law limiting the deduction for state and local taxes to $10,000 and the elimination of Employee business expenses and other miscellaneous expenses
- Elimination of Personal Exemptions. Generally, a single person or married couple with no kids that did not itemize is making out better here, but others are not.
- You have kids and one of them turned 17. This would make them ineligible for the child tax credit and only give you the $500 Other Dependent Credit for your child.
Overall, everyone has a different situation. The best way to figure out why your refund is different this year is to look at your 1040 for last year and compare it to this year. You will need to look at the words on the line and the schedules as the forms have totally changed this year.