Tax guide5 min read · Updated October 8, 2026

How to Estimate Your Tax Refund Before You File

Your refund is the tax you have already paid minus the tax you owe on your return. You can work it out from two forms you already have: your W-2 and your last pay stub.

By Amara Taylor

Estimate your refund in six steps

1. Gather your numbers. W-2 box 1 shows your wages and box 2 shows federal income tax withheld. If you worked more than one job, add each box across all your W-2s. Collect any 1099 forms for interest or side income too.
2. Add up your income. Wages plus other taxable income gives you your total income.
3. Subtract adjustments and the deduction. Take off adjustments such as IRA contributions, then your standard deduction. For 2025 the IRS standard deduction is $15,750 for single filers, $31,500 for married couples filing jointly and $23,625 for head of household. For 2026 it is $16,100, $32,200 and $24,150. What remains is taxable income.
4. Apply the brackets. Each slice of taxable income is taxed at its own rate. Only the part above a bracket line is taxed at the higher rate.
5. Subtract credits. The child tax credit reduces the tax directly and is worth up to $2,200 per qualifying child for 2025 and 2026. Up to $1,700 per child of it can be refunded if it is larger than your tax.
6. Compare with what you paid. Subtract total tax from the tax withheld plus any estimated payments. A positive number is your refund. A negative number is what you owe.

A worked example

A married couple filing jointly for 2025 earn $90,000 in wages, have two children under 17 and had $7,000 withheld.

The same couple with no children would have a total tax of $6,543 and a refund of $457. The credits did most of the work here, which is why leaving them out is the most common reason an estimate looks too low.

Why is my actual refund different from the estimate?

The estimate is only as complete as the inputs. The final return uses every form and credit that applies to you. These are the gaps that show up most often.

• Income you did not count. Interest, unemployment pay and side income all raise taxable income, and some of them have no tax withheld at all.
• Withholding that changed. A second job, a raise or a new W-4 mid-year can leave your last pay stub out of step with the W-2 total. Use the W-2 when you have it.
• Credits that were not entered. The child tax credit is only one. The earned income credit and education credits can move a refund by thousands of dollars, and a calculator can only include what you type in.
• The wrong deduction. Many filers take the standard deduction, but itemizing can come out higher if you have large mortgage interest, state taxes and gifts to charity.
• Rules that changed between years. The 2025 standard deduction rose to $15,750 from $15,000, and the child tax credit rose to $2,200 from $2,000, according to the IRS. An estimate built on last year’s figures will be off.
• Offsets and errors. The IRS lists math mistakes and a missing signature among the causes of delay. A refund can also be reduced to pay certain past-due debts.

Timing can differ from the estimate too. The IRS says an e-filed return takes about 3 weeks, that refunds on returns claiming the earned income credit are held until mid-February, and that the additional child tax credit needs more review time.

What to do if the estimate shows a balance due

You have two levers. You can adjust the tax withheld from your pay, or you can plan to pay the difference when you file. For withholding, the IRS Tax Withholding Estimator helps you work out the right amount and can produce a filled-in W-4. The IRS recommends checking your withholding every January and after life changes such as a new job, marriage or a child. Our guide to W-4 withholding shows which step of the form to change in each situation.

This guide is general information, not tax advice. Sources: IRS 2025 tax law changes, IRS Rev. Proc. 2025-32, IRS federal income tax rates and brackets, IRS child tax credit, IRS refunds. Figures last checked October 8, 2026. See our editorial standards.

Last updated: October 8, 2026 · Written by Amara Taylor, Content Lead, Anchor AI Tools.