Form 1040A and the Child Tax Credit (2018): A Complete Guide
What Form 1040A Was Used For (and What Changed in 2018)
Starting with the 2018 tax year, Form 1040A was discontinued by the IRS. If you previously used Form 1040A or Form 1040EZ, you now use the redesigned Form 1040 instead. The new Form 1040 replaced all previous versions and uses a “building block” approach with additional schedules (Schedules 1 through 6) for more complex situations. This guide explains how the Child Tax Credit worked for the 2018 tax year under this new system.
What the Child Tax Credit Is For
The 2018 Form 1040 is your main federal income tax return, and the Child Tax Credit is a valuable benefit claimed directly on this form. The Child Tax Credit helps families reduce their tax bill by up to $2,000 for each qualifying child under age 17.
The credit comes in two parts:
- Child Tax Credit (nonrefundable): Reduces your tax bill.
- Additional Child Tax Credit (refundable): Can refund up to $1,400 per child even if you owe no tax (claimed on Schedule 8812).
The 2018 tax law also introduced the Credit for Other Dependents (up to $500) for children age 17 or older or other qualifying dependents.
When You’d Use This (Late or Amended Returns)
Late Returns
If you never filed your 2018 return, you should file it as soon as possible. You generally have three years from the original due date to claim a refund. For 2018 returns, this meant the refund deadline was April 15, 2022.
Amended Returns
If you filed your 2018 return but made a mistake—such as forgetting to claim a qualifying child—you file Form 1040-X.
You generally have:
- Three years from the date you filed your original return
or - Two years from when you paid the tax
…whichever is later.
Certain 2018 changes from disaster relief laws also required amended returns.
Key Rules or Details for the 2018 Child Tax Credit
The Seven Requirements for a Qualifying Child
Each child must meet all seven IRS tests:
- Relationship test
- Age test (under 17 at end of 2018)
- Support test
- Residency test
- Dependent status
- Joint return test
- Citizenship/residency test
Social Security Number Requirement
A child must have an SSN valid for employment issued before the filing deadline.
ITINs and ATINs do not qualify for the Child Tax Credit.
Income Limits
The credit begins phasing out at:
- $400,000 for married filing jointly
- $200,000 for all other filers
Reduced by $50 for each $1,000 over the limit.
Earned Income Requirement for Additional CTC
You must have at least $2,500 of earned income to claim the refundable Additional Child Tax Credit.
Step-by-Step (High Level)
Step 1: Determine Eligibility
Review each child using the seven IRS tests and confirm SSN validity.
Step 2: Complete the Dependents Section on Form 1040
List each child, include their SSN, and check the “Child tax credit” box.
Step 3: Calculate Your Credit
Use the IRS worksheet from Form 1040 instructions or Publication 972.
Step 4: Apply Income Phaseouts
Reduce the credit if your income exceeds the threshold.
Step 5: Enter the Credit on Form 1040
Put the amount on line 12a.
Step 6: Complete Schedule 8812 (If Applicable)
Use Schedule 8812 to compute the refundable Additional Child Tax Credit, entered on line 17b.
Common Mistakes and How to Avoid Them
Missing or Invalid SSNs
Only SSNs valid for employment qualify. ITINs/ATINs do not.
Age Requirement Mistakes
Child must be under 17 at the end of 2018.
Incorrect Checkbox on Form 1040
Always check the correct “Child tax credit” box.
Misunderstanding Residency Rules
Child must live with you over half the year, with allowable temporary absences.
Claiming Ineligible Dependents
Citizenship/residency test errors are common—non-U.S. children generally do not qualify.
Forgetting Form 8862 After Prior Denial
If your CTC/ACTC was denied previously (not a math error), Form 8862 is required.
Calculation Errors
Most errors come from income phaseouts or misusing the worksheet.
What Happens After You File
Processing Timeline
Most e-filed returns are processed within 21 days, but refunds with the Additional Child Tax Credit cannot be issued before mid-February.
Refund Options
Direct deposit is fastest; paper checks take 4–6 weeks.
IRS Reviews or Audits
The IRS may request proof such as school, medical, or childcare records.
Math Error Notices
You have 60 days to contest corrections.
Future Year Implications
Eligibility must be re-verified each year.
FAQs
#### Can I claim the Child Tax Credit if my child doesn't have a Social Security Number yet?
No. A valid SSN issued before your filing deadline is required. Children with ITINs or ATINs may qualify for the $500 Credit for Other Dependents instead.
#### My child turned 17 in 2018. Can I still claim any credit?
You cannot claim the Child Tax Credit, but you may be eligible for the $500 Credit for Other Dependents if all other requirements are met.
#### I share custody. Who gets the Child Tax Credit?
The parent with whom the child lived the greater number of nights in 2018 generally gets the credit. Form 8332 alone does not transfer CTC rights.
#### What's the difference between the Child Tax Credit and the Additional Child Tax Credit?
- CTC: Nonrefundable
- Additional CTC: Refundable up to $1,400 per child, claimed on Schedule 8812
#### Do I need to send proof that my child lived with me?
Not when filing. But keep documents for 3 years in case the IRS requests them.
#### I forgot to claim the Child Tax Credit on my 2018 return. Can I still get it?
You may file Form 1040-X if you’re within the amendment window (typically until April 2022 for most 2018 returns).
#### Will claiming the Child Tax Credit delay my refund?
If you claim the Additional Child Tax Credit, federal law requires the IRS to delay your entire refund until mid-February.
