How Is My Tax Refund Calculated?

Q: Why is my refund smaller than last year with the same income?

Most often your withholding went down (W-4 or table changes), or a credit phased out as income crept up. Smaller refund with the same tax usually means you kept more in each paycheck — compare full-year withholding, not just the refund.

Q: Why do I owe tax instead of getting a refund?

Your paychecks withheld less than your actual tax — commonly from a second job, a raise with a stale W-4, or untaxed side income. File a new W-4 so next year corrects itself.

Q: Does a bigger salary mean a smaller refund?

Not by itself. Refund size depends on withholding, eligible refundable credits and total tax after nonrefundable credits. A higher salary can change both tax and credit eligibility, so income alone does not determine the refund.

The short answer: for this restricted 2026 W-2 estimate, your refund or amount owed is W-2 federal withholding plus eligible refundable ACTC and EITC, minus total federal income tax after eligible nonrefundable CTC/ODC. A positive balance is an estimated refund; a negative balance is an estimated amount owed. The 2026 Tax/EIC tables and related refund forms used here are drafts, so results are provisional.

Estimated balance = W-2 federal withholding + refundable ACTC + EITC − total tax after nonrefundable credits

→ Run your numbers in the 2026 W-2 refund estimator — nothing is uploaded.

The five steps below explain the income, tax and credits included in this restricted estimate.

Step 1: Add up your income

Start with everything that counts as taxable income for the year — wages, salary, tips, interest, unemployment benefits, and most other money that came in. For most W-2 filers this is simply Box 1 of your W-2.

Some money is not taxed at all (like certain retirement contributions) and never shows up in this step. That's why Box 1 can be smaller than your actual salary — it isn't a mistake.

This calculator accepts ordinary W-2 income only. Interest, investment income, self-employment income and other income sources require a different calculation.

Step 2: Subtract the standard deduction

Eligible filers can claim a standard deduction before tax rates apply. Its size depends on your filing status, and it changes most years (the 2026 amounts live in the calculator, which uses them automatically).

Alternative: you can instead itemize — add up mortgage interest, big medical bills, charitable donations, and a few other categories — and subtract that instead. You take whichever is bigger. Most people take the standard deduction because it's larger and requires no receipts.

This tool supports the ordinary standard deduction for eligible filers under 65 who do not qualify for the additional deduction for blindness and cannot be claimed as dependents. Itemized and other deductions are outside its scope.

Same income, same bracket — a bigger deduction means less income left to tax, which means a smaller "tax owed," which means a bigger refund.

Step 3: Run the brackets — on the remaining income

Here's the single most misunderstood part of US taxes: your bracket does not apply to all your income, only to the slice that falls in it.

Simplified example with made-up numbers — not the real 2026 brackets: say the first $20,000 of income is taxed at 10%, and everything above that at 12%. If you made $30,000, you pay 10% on the first $20,000 and 12% only on the remaining $10,000. You never pay 12% on the whole $30,000.

That's why "getting a raise pushed me into a higher bracket" almost never means a raise made you worse off — only the extra dollars above the line are taxed higher.

For taxable income below $100,000, this calculator uses the supplied 2026 IRS draft Tax Table. At $100,000 or more, it uses the ordinary-income worksheet calculation. The simplified bracket example above is explanatory, not the lookup used for smaller taxable incomes.

Step 4: Subtract credits — the most valuable dollars in the process

After the bracket math you have your base tax. Now credits subtract from that tax directly, dollar for dollar.

Credits vs deductions, in one line: a deduction shrinks the income your rate applies to; a credit shrinks the tax itself. That's why a $100 credit is worth more than a $100 deduction for almost everyone.

The Child Tax Credit applies to qualifying children under 17. This calculator includes eligible CTC/ODC, ordinary ACTC and EITC within its stated scope. Education credits, dependent-care credits and other credits are outside this version. It stops without an amount when the required ACTC calculation needs Schedule 8812 Part II-B.

One distinction that matters: some credits are refundable — they can push your refund above what you paid in. Nonrefundable ones can only bring your tax to zero, never below.

Step 5: Compare against what you already paid

In this tool, the payment side is full-year W-2 Box 2 federal withholding plus eligible refundable ACTC and EITC. Estimated tax payments and other payments are outside this version.

Payments and refundable credits > total tax → the difference is your estimated refund
Payments and refundable credits < total tax → the difference is your estimated amount owed
Equal → no estimated refund or amount owed

A refund may include both tax you overpaid and refundable credits. It can therefore exceed the federal income tax withheld from your paychecks.

Why your refund changed from last year

Three usual suspects:

Withholding tables or your W-4 changed — same tax, less taken out per paycheck = smaller refund (and bigger paychecks all year).
Life changed — a child turned 17 (Child Tax Credit drops off), a side gig appeared (no withholding on it), you got married or filed differently.
Income moved — into a bracket slice, or far enough up that credits began phasing out.

Compare your prior return with your current-year figures to understand the change. This calculator supports the 2026 tax year only.

Is a big refund actually good?

A refund can come from overwithholding, refundable credits, or both. The portion from overwithholding is money you could otherwise have received in your paychecks; refundable credits can create a refund even when little or no income tax was withheld.

If you want to adjust withholding, review your W-4 with your employer or use the IRS withholding guidance. This calculator estimates a 2026 refund or amount owed; it does not calculate W-4 settings or next year's withholding.

What this page does not cover

This restricted estimate does not model the federal-public-benefit adjustment shown on the draft 2026 Schedule 3-A. The applicable final rules and forms still require review before any claim of full 2026 return accuracy.

State refunds are a separate calculation with their own rules → State tax refund guide
Self-employment income, self-employment tax and quarterly estimated payments are outside this calculator’s scope; it returns no amount for those situations
Refund timing — when the money actually lands → When will I get my tax refund?

FAQ

Why is my refund smaller than last year with the same income? Most often your withholding went down (W-4 or table changes), or a credit phased out as income crept up. Smaller refund with the same tax usually means you kept more in each paycheck — compare full-year withholding, not just the refund.

Why do I owe tax instead of getting a refund? Your paychecks withheld less than your actual tax — commonly from a second job, a raise with a stale W-4, or untaxed side income. File a new W-4 so next year corrects itself.

Does a bigger salary mean a smaller refund? Not by itself. Refund size depends on withholding, eligible refundable credits and total tax after nonrefundable credits. A higher salary can change both tax and credit eligibility, so income alone does not determine the refund.