Is a big tax refund a good thing?

A tax refund is the IRS returning tax you paid during the year that you didn't owe. A big refund feels like a bonus, but it means your paychecks were smaller than they needed to be, and the IRS paid you no interest for holding the money.

Withholding is a prepayment

Each paycheck, your employer sends part of your pay to the IRS as an advance on your yearly income tax. When you file, you compare what was withheld with what you actually owe.

Refund or bill is the difference

Withheld more than your tax, and you get a refund. Withheld less, and you owe the rest by the filing deadline, usually April 15.

The W-4 controls the amount

Form W-4 tells your employer how much to withhold. It covers your filing status, other jobs, dependents, other income, deductions and any extra amount you want held back.

Owing a lot can cost a penalty

You generally avoid an underpayment penalty if you owe less than $1,000 at filing, or if you paid in at least 90% of this year's tax or 100% of last year's, whichever is smaller. If last year's adjusted gross income was over $150,000 ($75,000 if married filing separately), use 110% of last year's tax instead.

Where a refund comes from

Income tax is due as you earn, so the IRS collects it all year through withholding. Your employer guesses your yearly tax from your W-4 and your pay, then takes a slice from each paycheck.

The guess is rarely exact. A raise late in the year, a second job, a new child or a big deduction can all move your real tax away from what was withheld. Filing your return settles the gap in one direction or the other.

Why a big refund is not free money

A refund is your own pay, held by the IRS until you file. The IRS generally pays no interest on it. If you carry a credit card balance or have no emergency fund, that money would have done more work in your hands each month.

Some people like a refund because it works as forced savings. That is a fair choice. An automatic transfer to a savings account on payday does the same job and gives you access to the money if an emergency comes up in October.

How to change your withholding

Ask your employer or payroll site for a new Form W-4. You can submit one any time, and it usually takes effect within a pay period or two. The form has five steps: your details, multiple jobs or a working spouse, dependents and credits, other adjustments, and your signature.

To shrink a refund, claim credits you qualify for in Step 3 or add deductions in Step 4(b). To shrink a bill, add an extra dollar amount per paycheck in Step 4(c). The IRS Tax Withholding Estimator does this math for you and fills in the form.

If you end up owing

Owing a small amount at filing is normal and fine. File on time even if you can't pay in full, because the penalty for not filing is larger than the penalty for not paying. The IRS offers payment plans for balances you can't clear at once.

If you owed a large amount, fix it for next year. Raise your withholding with the estimator, or make quarterly estimated payments if you have self-employment or other income with no tax withheld.

When to check again

Run the estimator early in the year, again after any big life change, and once more in the fall while there are still paychecks left to adjust. Rules differ for state income tax, which has its own withholding form in many states.