5 Tax Mistakes That Cost W-2 Earners Thousands Every Year

There is a widespread belief that W-2 employees have simple tax situations. You get your paycheck, taxes are withheld, and you file a return in the spring. While that describes the mechanics, it does not capture the full picture. Millions of salaried workers leave money on the table every year because they assume their situation is too straightforward to require much attention. Here are five of the most costly mistakes we see.

1. Defaulting to the Standard Deduction Without Checking

The standard deduction is generous, and for most filers it makes sense. For 2023, it is $13,850 for single filers and $27,700 for married filing jointly. But that does not mean you should accept it without running the numbers.

If you own a home, pay state and local taxes in a high-tax state, make significant charitable contributions, or have substantial medical expenses, your itemized deductions may exceed the standard deduction. The only way to know is to calculate both. Many taxpayers who could benefit from itemizing never bother because they assume the standard deduction is always the better choice.

Even if itemizing does not make sense this year, understanding where you stand helps you plan. Strategies like bunching charitable donations into alternating years can push you over the threshold in the years you itemize.

2. Not Adjusting Your W-4 After Life Changes

Your W-4 determines how much federal tax your employer withholds from each paycheck. Most people fill it out when they start a job and never touch it again. That is a problem because your tax situation changes over time.

Getting married, having a child, buying a home, starting a side business, or even getting a raise can all shift your tax liability. If your withholding does not reflect those changes, you will either overpay throughout the year (giving the government an interest-free loan) or underpay (resulting in a surprise tax bill and potential penalties in April).

A mid-year W-4 review is one of the simplest things you can do to keep your cash flow aligned with your actual tax obligation. The IRS Tax Withholding Estimator is a free tool that can help you determine the right withholding amount.

3. Ignoring Above-the-Line Deductions

Above-the-line deductions reduce your adjusted gross income (AGI) regardless of whether you itemize. A lower AGI can unlock additional credits and deductions that phase out at higher income levels, making these deductions doubly valuable.

• Student loan interest: You can deduct up to $2,500 in student loan interest paid during the year, even if you take the standard deduction. Income phase-outs apply, but many early-career professionals qualify
• Educator expenses: Teachers and eligible educators can deduct up to $300 in unreimbursed classroom expenses. It is a small amount, but it is frequently missed
• HSA contributions: If you have a high-deductible health plan, contributions to a Health Savings Account are deductible above the line. For 2023, the limit is $3,850 for individuals and $7,750 for families. This is one of the most powerful tax-advantaged tools available
• Traditional IRA contributions: Depending on your income and whether you have access to an employer plan, traditional IRA contributions up to $6,500 ($7,500 if age 50+) may be fully or partially deductible

4. Missing Out on Tax Credits You Qualify For

Credits are more valuable than deductions because they reduce your tax liability dollar for dollar. Several credits are available to W-2 earners that are commonly overlooked.

• Saver's Credit: If your AGI is below certain thresholds ($36,500 single, $73,000 married filing jointly for 2023), you may qualify for a credit of up to $1,000 ($2,000 married) for contributing to a retirement account. This credit is designed for low- to moderate-income workers and is frequently missed by eligible filers
• Child and Dependent Care Credit: If you pay for daycare, after-school programs, or summer camps for children under 13 so you can work, you may qualify for a credit of up to $3,000 in expenses for one child or $6,000 for two or more
• Lifetime Learning Credit: If you are taking courses to improve your job skills or pursuing a degree, you may qualify for a credit of up to $2,000 per year. This credit has no limit on the number of years you can claim it
• Energy-efficient home improvement credits: Under the Inflation Reduction Act, homeowners can claim up to $3,200 per year for qualifying energy-efficient improvements like heat pumps, insulation, windows, and doors

5. Filing Without Professional Guidance When Your Situation Warrants It

Tax software is convenient, but it only knows what you tell it. It does not ask probing questions about your financial goals, it does not flag planning opportunities for next year, and it does not catch situations where a different filing strategy could save you more.

If you had a major life event during the year, if you own rental property, if you received stock options or RSUs, or if you are earning above $150,000, working with a tax professional can uncover savings that far exceed the cost of preparation. The value is not just in the return itself but in the forward-looking advice that comes with a professional relationship.

Key Takeaways

• Run the numbers on itemizing versus the standard deduction before defaulting to one or the other
• Update your W-4 after any major life change to keep withholding accurate
• Claim every above-the-line deduction you qualify for to reduce your AGI
• Do not overlook credits like the Saver's Credit, dependent care credit, and energy improvement credits
• Consider professional tax preparation if your situation has any layers of complexity