Yes! You can use AI to fill out Form TC-40, Utah Individual Income Tax Return

Filers often select the wrong numeric code for their filing status on line 1, such as choosing 'Single' (code 1) when they qualify for 'Head of Household' (code 4). This mistake significantly impacts tax calculations, exemptions, and credits, potentially leading to overpayment of tax or an incorrect refund amount. Always review the specific criteria for each filing status in the form instructions to ensure you select the most beneficial and accurate option.

The form requires filers to categorize dependents on lines 2a, 2b, and 2c before totaling them on line 2d. A common error is double-counting a dependent or miscategorizing them, which leads to an incorrect total on line 2d. This directly causes a miscalculation of the Utah personal exemption on line 11, altering the final tax liability and potentially triggering a review by the tax commission.

Line 4 requires the AGI from the filer's federal return, but people sometimes mistakenly enter their federal taxable income or another figure. This foundational error throws off all subsequent calculations on the state return, from total income (line 6) to the final tax due or refund. To prevent this, carefully locate the final AGI on your completed federal Form 1040 and transcribe it exactly to line 4.

The multi-step calculation for the Taxpayer Tax Credit (lines 10 through 20) is a frequent source of errors. Mistakes include using the wrong percentage for multiplication (e.g., 4.5% instead of .045), simple arithmetic errors in addition or subtraction, or failing to ensure a result is 'not less than zero'. An error here directly impacts the Utah income tax on line 22 and can result in an incorrect tax assessment and processing delays.

The form explicitly states when another form or schedule must be attached, such as TC-40A for income additions/subtractions (lines 5 and 8) or TC-40W for withholding details. Filers often complete the main TC-40 but forget to include these mandatory attachments with their submission. This is a major processing error that will halt the return, significantly delaying any refund and prompting a notice from the Utah State Tax Commission requesting the missing documents.

Transposing digits in a Social Security Number (SSN) or entering a spouse's or dependent's SSN that does not match the name provided is a critical error. The tax commission uses SSNs to verify identities and cross-reference income data. A mismatch will cause the return to be rejected or flagged for identity verification, leading to substantial delays in processing and receiving a refund.

When entering bank routing and account numbers for a direct deposit refund, even a single incorrect digit can cause major problems. This mistake can result in the refund being delayed for weeks or, in a worst-case scenario, sent to the wrong account. To avoid this, carefully double-check the numbers from a check or bank statement and confirm whether the account is checking or savings. AI-powered form fillers like Instafill.ai can help by validating the format of routing numbers.

When entering withholding information from a W-2 on the TC-40W schedule, the 'Utah Withholding ID Number' has a strict format: 14 characters ending in 'WTH' with no hyphens. Many filers enter the number with hyphens or omit the 'WTH' suffix, copying it exactly as it appears elsewhere. This formatting error can cause the system to reject the withholding credit, leading to a tax-due notice for the full amount because the prepayment cannot be verified automatically.

When amending a return, filers must enter the specific 'Amended Return' code and fill out fields for previous refunds or payments. A common mistake is to simply correct the numbers on a new form without indicating that it is an amendment. This causes the tax commission to process it as a duplicate original return, creating significant confusion, erroneous notices, and a lengthy process to resolve the account.

Lines 5 and 8 require filers to report income adjustments from schedule TC-40A, but they may misclassify items, such as reporting a subtraction as an addition. This often happens due to misunderstanding the complex rules for what qualifies as a state-level income adjustment. This error directly impacts the Utah taxable income on line 9 and can lead to paying tax on non-taxable income or incorrectly reducing tax liability, resulting in future penalties. If the form is a non-fillable PDF, a tool like Instafill.ai can convert it to a fillable version, making it easier to navigate and fill accurately.