After subtracting your adjustments and deductions from your gross income, you have your taxable income. Now you can use the IRS’s tax table to calculate your preliminary tax liability for the year.

The individual income tax rate (2019) structure is a progressive tax rate structure.

2019 Tax Rate	Single	Head of Household	Married Filing Jointly	Married Filing Separately
10%	$0–$9,700	$0–$13,850	$0–$19,400	$0–$9,700
12%	$9,701–$39,475	$13,851–$52,850	$19,401–$78,950	$9,701–$39,475
22%	$39,476–$84,200	$52,851–$84,200	$78,951–$168,400	$39,476–$84,200
24%	$84,201–$160,725	$84,201–$160,700	$168,401–$321,450	$84,201–$160,725
32%	$160,726–$204,100	$160,701–$204,100	$321,451–$408,200	$160,726–$204,100
35%	$204,101–$510,300	$204,101–$510,300	$408,201–$612,350	$204,101–$306,175
37%	Over $510,300	Over $510,300	Over $612,350	Over $306,175

For example, if: a taxpayer with a single filing status has $92,000 of taxable income. The income tax liability in 2019 is calculated as the below:
($9,700 − $0) × 10% = $970
($39,475 − $9,700) × 12% = $3,573
($84,200 − $39,475) × 22% = $9,840
($92,000 − $84,200) × 24% = $1,872
Total income tax liability is $970 + $3,573 + $9,840 + $1,872 = $16,255

You can subtract tax credits you qualify for from this amount. Common credits include: Child Tax Credit, Credit for Other Dependents, Foreign tax credit etc. Then you can add other taxes to this amount, including self-employment tax (Schedule 2 should be attached). The result will be your total tax.

The next step is to calculate the taxes that you have already paid for the year (this includes taxes withheld from Forms W-2 and 1099). Subtract the amount from your total tax. If the number is positive, this is the amount you owe. If the number is negative, this is the amount of the refund you are entitled to.

Download： U.S. Individual Income Tax Part 6 Tax Liability or Refund [PDF]