Updated October 17, 2026. Quick answer: Line 34 is the amount you overpaid, found by subtracting line 24 from line 33. On line 35a you enter how much of it you want refunded, and lines 35b to 35d hold your routing number, account type and account number for direct deposit. Line 36 is the part you want applied to your 2026 estimated tax.
Related reading on this site: IRS Publication 596.
Related reading on this site: IRS Notice CP05 (refund verification hold), IRS Notice CP05A (documents to verify wages and withholding), IRS Notice CP59 (no record of your prior year return) and IRS Notice CP515 (reminder: no record of prior returns).
Business use of your home (Form 8829), the saver’s credit (Form 8880), clean vehicle credits (Form 8936) and amended returns (Form 1040-X), read line by line: Form 1040-X, Form 1040-X lines 18 to 23 and Form 1040-X Parts II and III.
Line 34: the amount you overpaid
The form’s caption for line 34 reads “If line 33 is more than line 24, subtract line 24 from line 33. This is the amount you overpaid”. The instructions add one small rule: “If line 34 is under $1, we will send a refund only on written request.” Line 34 is filled in only when you paid in more than you owe. If you owe instead, line 34 stays empty and the balance goes on line 37.
Line 35a: the amount refunded to you
The form’s caption for line 35a reads “Amount of line 34 you want refunded to you. If Form 8888 is attached, check here”. You can ask for all of line 34 or only part of it, because the rest can go to line 36. For checking a refund, the instructions say “If you want to check the status of your refund, just use the IRS2Go app or go to IRS.gov/Refunds.” They also tell you what to have ready: “Have your 2025 tax return handy so you can enter your social security number, your filing status, and the exact whole dollar amount of your refund.”
A labelled illustration, not an IRS example, of the form’s arithmetic: if line 34 is $700 and you want $500 refunded, you enter $500 on line 35a, and the remaining $200 can go on line 36. The figures are made up to show the arithmetic only.
Lines 35b to 35d: direct deposit
The instructions describe the deposit this way: “Have your refund deposited automatically to your checking or savings account, including an individual retirement arrangement (IRA).” For a single account, they say to “Complete lines 35b through 35d”. Each of the three lines has its own rule.
Line 35b is the routing number: “The routing number must be nine digits.” “The first two digits must be 01 through 12 or 21 through 32.” Line 35c is the account type: “Check the appropriate box for the type of account. Don’t check more than one box.” Line 35d is the account number: “The account number can be up to 17 characters (both numbers and letters).” “Don’t include the check number.”
Splitting a refund and whose account it goes to
To send the refund to more than one account, the instructions say to “Check the box on line 35a and attach Form 8888”. The limit is stated this way: “Your refund can be split and directly deposited into up to three different accounts in your name on Form 8888.” The form is covered on the Form 8888 page.
The account has to be yours: “Account must be in your name.” The instructions give a specific example, “such as your tax return preparer’s account”, and say not to use it even to pay a preparation fee. There is also a yearly cap: “The number of refunds that can be directly deposited to a single account or prepaid debit card is limited to three a year.”
Reasons a direct deposit request is rejected
The instructions list conditions under which “your direct deposit request will be rejected and your refund may be delayed”. They include “You haven’t given a valid account number.” and “Any numbers or letters on lines 35b through 35d are crossed out or whited out.” They also warn “The IRS isn’t responsible for a lost refund if you enter the wrong account information.” The practical step they give is “Check with your financial institution to get the correct routing and account numbers”.
Line 36: applied to your 2026 estimated tax
The form’s caption reads “Amount of line 34 you want applied to your 2026 estimated tax”. The instructions say “Enter on line 36 the amount, if any, of the overpayment on line 34 you want applied to your 2026 estimated tax.” They also include a warning: “This election to apply part or all of the amount overpaid to your 2026 estimated tax can’t be changed later.” For how estimated payments work, see the Form 1040-ES page.
Where it goes next
These lines split the overpayment from line 34. The instructions for line 38 tie them together: “Lines 35a, 36, and 38 must equal line 34.” That means any estimated tax penalty on line 38 reduces the amount you can put on line 35a or line 36. The wider layout is in Form 1040 line by line.
Edition and line numbers
This page reads the 2025 Form 1040 and its 2025 instructions, the current files irs.gov served on 2026-10-17. They are the forms for the tax year 2025 return, filed in 2026. The instructions say “The lines on Forms 1040 and 1040-SR are the same.” so everything here applies to Form 1040 and to Form 1040-SR alike. Check the tax year printed on the form you are filling in and use the line numbers on that year’s form, because a different year’s form can number or word its lines differently.
Common mistakes
- Entering a routing number that cannot be right. The instructions say “The routing number must be nine digits.”
- Checking both boxes on line 35c. The instructions say “Don’t check more than one box.”
- Using an account that is not yours. The instructions say “Account must be in your name.” and give a preparer’s account as the example to avoid.
Related: Form 8888, Form 1040-ES, Form 1040 line 37, and estimated tax due dates.
Sources
- Instructions for Form 1040 and Form 1040-SR (2025): https://www.irs.gov/pub/irs-pdf/i1040gi.pdf
- Form 1040, U.S. Individual Income Tax Return (2025): https://www.irs.gov/pub/irs-pdf/f1040.pdf
Read from the IRS documents linked above on October 17, 2026. General information, not tax advice. Your own facts decide the outcome, and a preparer, the account provider or the IRS is the right place to confirm anything consequential.