fyllyoThe same amount on two documents
An IRA distribution is on the 1099-R and again in a preparer’s draft. Software can add both and double the income.
TAX FORMS · IRS · BUILT IN
Fill Form 1040 with AIU.S. Individual Income Tax Return
Add the organizer, the W-2s, the 1099s and any workpapers. Fyllyo fills Form 1040 on your Mac, shows the lines behind each answer and leaves anything it can’t settle for you, with the reason.
Where AI form filling goes wrong on Form 1040
Form 1040 gathers a whole year from many documents: W-2s, a stack of 1099s, an organizer, last year’s figures and often a preparer’s draft. The same amount can appear in three places, and every document carries numbers that belong somewhere else. These are the common places AI tools and autofill get it wrong. What the form requires is for the IRS to say. Follow its instructions. IRS instructions for Form 1040.
Last year’s figure beside this year’s
Year-end statements often print the prior year’s amount for comparison. Software can take it for the current year.
Every tax on the W-2 taken as income tax
A W-2 shows federal income tax, Social Security tax and Medicare tax withheld side by side. Software can add them together.
A payment that belongs on another form
A file can hold a distribution the documents say goes on a separate form, such as a beneficiary’s lump sum. Software can fold it into the pension lines.
A masked account number
A voided deposit slip often shows only the last digits of the account. Software can copy the masked number into the refund boxes.
Four dependents, two kinds of credit
The dependents table has a row per person and a credit box on each. Software can shift a box onto the wrong row.
The home the couple left
A tax organizer can keep the household’s previous home, marked as no longer used. Software can put that street on the return.
How Fyllyo takes care of them
With a test client and four documents (a tax organizer, a W-2, a consolidated statement with four 1099s and the preparer’s draft computation), Fyllyo filled 84 fields in 113 seconds. It left 6 for the preparer, the Social Security numbers the documents show only masked, each with the reason.
- The same amount on two documents. Counts a repeated amount once and shows every line it was read from. In the test, the taxable IRA amount stayed 3,000.
- Last year’s figure beside this year’s. Reads the current year only. In the test, taxable interest was 450, not the 2024 comparison of 392.18.
- Every tax on the W-2 taken as income tax. Takes withholding from box 2 alone. In the test, line 25a was 9,850, without the Social Security and Medicare amounts.
- A payment that belongs on another form. Keeps it off. In the test, the lump sum marked for Form 4972 stayed out of lines 5a and 5b, which came to 34,000 and 20,000 from the pension statement.
- A masked account number. Fills the full number from the document that prints it. A number shown only masked, like the SSNs in the test, is left for the preparer.
- Four dependents, two kinds of credit. Fills each dependent on their own row with the credit the organizer gives. In the test, two rows took the child tax credit and two the credit for other dependents.
- The home the couple left. The return carries the Hartford home from the organizer. The New Britain street, marked do not use since 2024, appeared nowhere.
How much of a Form 1040 does Fyllyo fill?
Fyllyo can fill all 199 fields on Form 1040 from the client’s documents. Lines the documents don’t support stay blank and are listed for you to check.
You confirm on every form
- Taxpayer's first name and middle initial
- Taxpayer's last name
- Taxpayer's social security number
- Total income
- Adjusted gross income
- and 4 more
What do you give Fyllyo?
Fyllyo reads the documents you already have. These can be PDFs, scans, photos, Word files or typed notes, and you can add several at once. Fyllyo works out which document answers which line.
Client data stays on your Mac
Client documents and the filled form never leave your computer. Fyllyo uploads nothing. Once it is set up, filling works offline.
What Fyllyo doesn’t do
Fyllyo doesn’t decide what to file, give legal or tax advice, or submit Form 1040 for you. Use the IRS’s instructions for Form 1040 and your professional judgement. Fyllyo does the reading and the typing.
Which edition of Form 1040 does Fyllyo fill?
The built-in Form 1040 is the 2025 version. For a different edition, add that fillable PDF as your own form. You set it up once, then fill it like this one. Set up that fillable PDF as your own form →
What if a document is a scan or a photo?
Fyllyo reads scans and photos as well as PDFs, Word files and typed notes. Clear, readable copies give the best results, and every answer on Form 1040 still shows the line it came from.
Fill your next Form 1040 on your Mac
Try form filling free for 5 days. Then buy Fyllyo Paid once for $99. It is a lifetime licence with free updates and no subscription. Filling forms on your Mac uses no AI credits. Pricing and licence details.