Line 2b of Form 1040 is where you report your total taxable interest income for the year. Add up every dollar of interest you received from banks, bonds, CDs, money market accounts, private loans, and any other source, then enter that single total. The number flows into your adjusted gross income and affects the tax you owe, so it needs to match what the IRS already has on file from the payers who sent you 1099s.
What Goes Into the Total
Taxable interest is money someone paid you for the use of your funds. The IRS treats it as received the moment it was credited to an account you could withdraw from, whether or not you actually took the cash out.1Internal Revenue Service. Publication 550 (2025), Investment Income and Expenses
The common sources:
- Savings accounts, interest-bearing checking, and certificates of deposit
- Corporate bonds, Treasury bonds, and Treasury bills
- Money market accounts at banks or brokerages
- Interest on private loans you made, including seller-financed mortgages
- Original Issue Discount (OID) on bonds you hold, which counts as interest each year even though the cash doesn’t arrive until the bond matures
Your main source document is Form 1099-INT. Banks and other payers send one whenever they paid you $10 or more in interest.2Internal Revenue Service. About Form 1099-INT, Interest Income Box 1 is your ordinary taxable interest. Box 3 is interest on U.S. savings bonds and Treasury obligations, which is federally taxable and belongs on Line 2b even though it’s exempt from state tax. If you hold a discount bond, you may also receive Form 1099-OID, and the OID amount gets added into the same total.
You still owe tax on interest even when no 1099 arrives. A bank that paid you $8 won’t generate a form, but that $8 is taxable and belongs in your total.3Internal Revenue Service. Topic No. 403, Interest Received The same goes for interest from a private loan or from a partnership reported to you on Schedule K-1.1Internal Revenue Service. Publication 550 (2025), Investment Income and Expenses
What Stays Off Line 2b
Interest from state and local government bonds, usually called municipal bonds, is generally exempt from federal income tax and does not go on Line 2b. Neither does interest earned inside a traditional IRA, Roth IRA, 401(k), or other tax-advantaged retirement account. Interest on Series EE or Series I savings bonds used for qualified higher education expenses can also be excluded, subject to income phaseouts.
Tax-exempt interest still has to be reported, just not on Line 2b. It goes one line up, on Line 2a. The IRS uses that figure in other calculations, including how much of your Social Security benefits are taxable, so don’t drop it entirely and don’t blend it into Line 2b.
Adjustments That Reduce the Number
The total on your 1099s isn’t always the final number for Line 2b. A few situations let you subtract.
Nominee Interest
If a 1099-INT came in your name but part of the interest actually belongs to someone else, that portion is nominee interest. On Schedule B, list the full 1099 amount, then subtract the nominee portion on a separate line labeled “Nominee Distribution.” Only the reduced total carries to Line 2b.4Internal Revenue Service. Instructions for Schedule B (Form 1040) You also need to issue a 1099-INT to the actual owner, unless that person is your spouse, and file a copy with the IRS.
Accrued Interest on Bonds You Bought
Buy a bond between interest payment dates and you typically pay the seller for interest that accrued before you owned it. The next payment shows up on your 1099-INT in full, including that pre-purchase slice. List the full 1099 amount on Schedule B, then subtract the accrued interest you paid at purchase on a line labeled “Accrued Interest.”5Internal Revenue Service. Instructions for Schedule B (Form 1040)
Amortizable Bond Premium
If you paid more than face value for a taxable bond, you can elect to amortize the premium and offset the bond’s interest income each year. The election covers every taxable bond you hold that year and going forward. You offset the interest on your return and attach a statement noting the election under Treasury Regulation 1.171-4.6eCFR. 26 CFR 1.171-4 – Election to Amortize Bond Premium on Taxable Bonds
When Schedule B Is Required
Schedule B is the worksheet where you list each interest source individually and arrive at the number that goes on Line 2b. File it if any of these apply:7Internal Revenue Service. About Schedule B (Form 1040), Interest and Ordinary Dividends
- Your taxable interest exceeds $1,500 for the year
- You received interest from a seller-financed mortgage where the buyer used the property as a personal residence
- You are claiming the education savings bond exclusion for Series EE or I bonds issued after 1989
- You have a financial interest in or signature authority over a foreign financial account
If your taxable interest is $1,500 or less and none of the other triggers apply, skip Schedule B and enter the total directly on Line 2b.
Foreign Accounts
Part III of Schedule B asks whether you have a financial interest in or signature authority over any foreign financial accounts. A “yes” can pull in two separate filings outside the tax return itself: FinCEN Form 114 (the FBAR) if the combined value of your foreign accounts topped $10,000 at any point during the year,8Internal Revenue Service. Report of Foreign Bank and Financial Accounts (FBAR) and Form 8938 with your return if your foreign financial assets cross the thresholds that apply to your filing status and residency.9Internal Revenue Service. Do I Need to File Form 8938, Statement of Specified Foreign Financial Assets The interest itself still lands on Line 2b like any other taxable interest.
A Child’s Interest
If your child had only interest and dividend income totaling less than $13,500, you can elect to fold it into your return using Form 8814 instead of filing a separate return for the child.10Internal Revenue Service. Topic No. 553, Tax on a Child’s Investment and Other Unearned Income For 2026, the first $1,350 of a child’s unearned income is generally tax-free, the next $1,350 is taxed at the child’s rate, and anything above $2,700 is taxed at the parent’s marginal rate under the kiddie tax. Above $2,700, if you don’t make the election, the child files their own return and uses Form 8615.
What Happens If the Number Is Wrong
The IRS receives copies of the same 1099-INT forms you do. Its Automated Underreporter program matches those third-party reports against what you put on your return, and mismatches generate a CP2000 notice proposing additional tax.11Internal Revenue Service. Topic No. 652, Notice of Underreported Income – CP2000
Leaving out interest that appeared on a 1099 is specifically cited by the IRS as an example of negligence, which carries an accuracy-related penalty of 20% of the underpaid tax.12Internal Revenue Service. Accuracy-Related Penalty Fraud raises the penalty to 75% of the underpayment attributable to the fraud.13Office of the Law Revision Counsel. 26 USC 6663 – Imposition of Fraud Penalty Interest on the unpaid tax runs from the original due date until you pay.
Before you file, put each 1099-INT next to your own records and reconcile them. If you earned interest the IRS knows about and you don’t, that’s the mismatch that generates the letter.