Free vs paid pay stub generators: what is the catch?

Most pay stub generators work the same way: a short web form, a few inputs, and a PDF in a couple of minutes. The question is not whether the output looks right, but whether the numbers behind it are right. For many free tools, they are not.

SimpleStub makes pay stubs. It does not file taxes, move money, or give tax advice.

What does a free pay stub generator actually do?

Most free generators are templates, not calculators. They format whatever you type into a professional-looking document and call it a pay stub. No withholding table is consulted. No wage base is checked. The federal income tax line is whatever you enter.

Paid generators typically do compute gross-to-net: they apply the IRS percentage method tables from IRS Publication 15-T for federal withholding, handle the Social Security wage base cap and the Additional Medicare Tax threshold (see IRS Topic No. 751), and carry state income tax for most states. That is genuine work and it is worth something. The per-stub price for most of these tools is a few dollars, and the first stub is often free.

The honest summary: free usually means no math. Paid usually means some math. Neither one is payroll.

What are the red flags to watch for?

Before trusting any tool, check for these:

• "100% accurate" claim alongside a "not a legal document" disclaimer. These two statements are in direct tension. A tool cannot guarantee accuracy and simultaneously disclaim responsibility for the output. One of them is doing more work than the other.
• Correct tax math or an "edit taxes" option sold as a paid add-on. If the base tier does not compute withholding you can trust, the base tier is not a tax-correct pay stub generator.
• Watermark removed after purchase. This framing implies that the free version is intended to look official before payment is confirmed. It is fraud-adjacent and has been used to fabricate stubs.
• YTD that does not accumulate. If the tool resets between sessions and recomputes YTD from what you type, stubs for the same employee can contradict each other. Internal YTD inconsistency is the single clearest sign that a stub was not issued by a system with memory.
• No employer record. If the tool cannot confirm that a specific stub was issued, there is no way to verify it later. A landlord, lender, or auditor who asks for confirmation gets nothing.
• A subscription that auto-renews for a one-time need. Some tools default to recurring billing. If you need one stub, confirm what you are agreeing to before you enter payment details.

How do you compare tools on tax correctness?

Everyone claims multi-state support, accurate withholding, and full-year YTD. The claim costs nothing. What actually differentiates tools is whether the math holds up in edge cases.

Run a known-value test before committing to any tool: enter a gross pay and withholding inputs you can hand-check, and see whether the federal and state tax lines match what the IRS tables produce. This takes five minutes and eliminates most weak tools.

When is a cheap per-stub tool actually the right choice?

For a single throwaway stub when speed and cost are the only considerations, a per-stub tool is hard to beat on price. If the recipient only needs a formatted document and you are going to verify the numbers manually anyway, the economics are simple.

The trade-off becomes unfavorable when:

• You have more than one stub to issue for the same employee across the year, because YTD integrity starts to matter.
• You have employees in multiple states with reciprocity agreements or local taxes, because "supports all 50 states" rarely means the edge cases are handled.
• The stub will be used for income verification by a lender or housing provider, because a tool with no audit trail cannot corroborate the document later.
• You employ F-1 or other nonresident-alien workers, because FICA-exemption handling is absent across most of the category.
• You want the employer's logo on the stub without paying an upcharge to remove a watermark.

What should the stub itself contain?

A correctly issued stub shows, at minimum:

• Employer name and employee name
• Pay period dates and pay date
• Gross pay for the period and year-to-date
• Each deduction and tax, itemized, with current and YTD amounts
• Net pay
• No blank or implausible fields

The YTD figures for Social Security and Additional Medicare Tax matter in particular. Social Security withholding stops at the annual wage base. Additional Medicare Tax applies only above a separate threshold. A stub that keeps withholding Social Security after the cap, or that misses the Additional Medicare Tax, is wrong in ways that add up over the year.

What does SimpleStub do differently?

SimpleStub computes withholding using the IRS percentage method tables, applies the Social Security wage base cap and the Additional Medicare Tax threshold, and handles F-1 / nonresident-alien FICA exemptions under IRC 3121(b)(19). It issues stubs against a running YTD record so stubs for the same employee do not contradict each other. The employer's branding is on the output by default. There is an audit trail.

It is not payroll. It does not file taxes, generate W-2s, or move money. If you need payroll, you need payroll software. But if you need a correct, verifiable, durable pay stub, the bar the category mostly does not clear is the one SimpleStub is built to.