The IRS tax filing deadline for 2025 returns is April 15, 2026, which is exactly one week from today, and if you have not filed yet, you are not alone. The IRS reported that as of late March, approximately 40% of expected individual returns had not yet been submitted, which tracks with the historical pattern of millions of Americans waiting until the final two weeks to file. The problem with filing under pressure is not just the stress. It is the mistakes. Errors on tax returns cost taxpayers billions of dollars in lost refunds, unnecessary penalties, and audit triggers every year, and most of them are entirely preventable if you slow down enough to check your work before you hit submit.
The single most common mistake, and the one that delays the most refunds, is entering incorrect Social Security numbers. It sounds too simple to be a real problem, but the IRS rejects or flags hundreds of thousands of returns every year because a digit was transposed, a dependent's number was entered incorrectly, or a name did not match the Social Security Administration's records. When this happens, the return gets kicked into manual processing, which can delay a refund by eight to twelve weeks compared to the typical 21-day turnaround for e-filed returns. If you are filing for yourself, a spouse, and dependents, triple-check every Social Security number on the return before you submit. It takes thirty seconds and can save you months of waiting.
The second category of costly mistakes involves claiming the wrong filing status. Taxpayers who are recently divorced, recently widowed, or who have a complex household situation sometimes choose a filing status that costs them money without realizing it. A qualifying surviving spouse, for example, can use the married filing jointly status for two years after the death of a spouse, which preserves higher standard deduction amounts and more favorable tax brackets. Head of household status provides significantly better tax treatment than single status, but you must meet specific requirements including maintaining a home for a qualifying dependent for more than half the year. Choosing single when you qualify for head of household can mean leaving $2,000 to $4,000 on the table depending on your income, and that adds up quickly when combined with other missed deductions and credits.
Speaking of missed credits, the Earned Income Tax Credit remains one of the most under-claimed benefits in the entire tax code. The IRS estimates that roughly 20% of eligible taxpayers do not claim the EITC, leaving an average of $2,500 to $3,500 per household uncollected. The credit is refundable, meaning it can result in a refund even if you owe no tax, and the income limits are higher than many people assume. For 2025, a married couple filing jointly with three or more qualifying children could earn up to $63,398 and still qualify for a partial credit, with the maximum credit amount reaching $7,830. Many taxpayers skip the EITC because they believe it only applies to very low-income households, but the phase-out ranges are broad enough to include families earning solidly middle-class incomes, particularly if they have multiple children.
For those who know they cannot file by April 15, the extension process is straightforward but widely misunderstood. Filing Form 4868 gives you an automatic six-month extension to file your return, moving the deadline to October 15, 2026. What it does not do is extend the time to pay what you owe. If you expect to owe money and file an extension without making a payment, you will accrue interest and late payment penalties starting April 16, even though your filing deadline has been extended. The penalty for failure to pay is 0.5% of the unpaid balance per month, and the interest rate is currently set at 7% annually, compounded daily. The smart move if you need an extension and think you might owe is to estimate your tax liability and send a payment with your extension request, even if the estimate is not perfect. Overpaying slightly is far cheaper than the combined cost of penalties and interest on an underpayment.
One final mistake that catches people every year involves cryptocurrency and digital asset reporting. Starting with the 2024 tax year and continuing for 2025 returns, the IRS requires taxpayers to answer a question about digital asset transactions directly on Form 1040. If you sold, exchanged, or received cryptocurrency or NFTs during 2025, you must answer yes and report the transactions, even if the amounts were small or you had a net loss. Failing to report crypto transactions is one of the fastest-growing audit triggers in the IRS enforcement pipeline, and the agency has invested heavily in blockchain analytics tools that can trace transactions across wallets and exchanges. The days of crypto flying under the radar are over, and the cost of non-compliance, including potential fraud penalties, is not worth the risk of skipping the reporting requirements.