Filing a tax return is one of the most important financial obligations many Americans have on an annual basis. However, not everyone is required to complete this task. Those with lower incomes may not have to -- although there are circumstances when they may wish to do so anyway. 

Here's what you need to know about when a tax return is required. 

1040 form with pen and calculator.

Image source: Getty Images.

Who has to file a tax return?

You only have to file a tax return if your income exceeds a certain threshold. That threshold depends on your filing status. The table below shows how much you can earn without having to file for the 2020 tax year by the April 15 deadline if you are not claimed as a dependent.

If your filing status is

And this is your age at the end of 2020

You must file once your income is at least

Single

Under 65

$12,400

Single

65 or older

$14,050

Married filing separately

All ages

$5

Head of household

Under 65

$18,650

Head of household

65 or older

$20,300

Married filing jointly

Both spouses under 65

$24,800

Married filing jointly

One spouse under 65

$26,100

Married filing jointly

Both spouses 65 or older

$27,400

Qualifying widow or widower with dependent child

Under 65

$24,800

Qualifying widow or widower with dependent child

65 or older

$26,100

Data source: IRS.

What if you are claimed as a dependent?

When you are claimed as a dependent, the rules are different. The table below shows when dependents are required to submit a return, based on filing status. 

If your filing status is And you are You must file if one of the following are true
Single Under 65

Your earned income is over $12,400 or $14,050 if you're blind

You have more than $1,100 in unearned income

Single Over 65 

Your earned income is over $14,050 or $15,700 if you're blind

You have more than $2,750 in unearned income

Head of household Under 65

Your earned income is over $18,650 or $20,300 if you're blind

You have more than $1,100 in unearned income

Head of household Over 65

Your earned income is over $20,300 or $21,950 if you're blind

You have more than $4,400 in unearned income

Married Under 65

Your earned income is over $12,400 or $14,050 if you're blind

Your unearned income is over $1,100

Your income is at least $5 and your spouse filed a separate return and itemized deductions

Married Over 65

Your earned income is over $14,050 or $15,700 if blind

Your unearned income is over $2,400

Your income is at least $5 and your spouse filed a separate return and itemized deductions

Data source: IRS.

If you aren't sure if you need to file, the IRS has an Interactive Tax Assistant tool you can use to determine if you're obligated to send in a 1040 form. 

Should you file even if you aren't required to? 

If you are not required to submit a tax return, you may want to do so anyway in order to obtain a refund of any excess taxes collected from your paychecks. In addition, many of those who qualify for refundable tax credits, such as the earned income tax credit and portions of the child tax credit, need to file in order to get the money they have coming to them.

If you didn't receive a coronavirus stimulus check but were entitled to one in 2020, you may also claim your money by filing a return, as the checks were an advance on a tax credit that you'd still be entitled to receive.

In other words, if the IRS owes you money, you should file a return to take the opportunity to claim it even if you aren't required to do so.