Figuring out whether a marketplace or payment app is likely to send you a Form 1099-K is arithmetic anyone can do — if they have the right figure. The problem is that the right figure depends on the tax year, sometimes on your state, and always on treating each platform separately, and a quick manual check often misses one of those without any sign that something was skipped.
| Step | Common mistake looking it up yourself | What this checker does |
|---|---|---|
| Picking the right year's figure | Using whatever number a search result or old bookmark shows, which may be last year's transition-relief figure ($5,000 for 2024 only) instead of the current $20,000/200 standing rule, or vice versa. | Applies the correct federal figure for the exact tax year you enter, and shows a note when that year had a one-off wrinkle (2024). |
| Reading "exceeds" vs. "at least" | Rounding "exceeds $20,000 and exceeds 200 transactions" up to "at least," which gets a seller sitting at exactly $20,000 across exactly 200 transactions the wrong answer. | Applies the IRS's own strictly-greater-than wording every time, with no rounding. |
| Combining platforms | Adding up what every platform paid you before comparing to the threshold, when the rule applies per platform, not to your total marketplace income. | Checks each platform you enter on its own, against its own total. |
| Checking for a state override | Not knowing that Maryland, Massachusetts, Vermont, and Virginia each set their own $600 threshold, independent of the federal figure and easy to miss if you only check the federal rule. | Applies each of those four states' own stricter threshold automatically when you select your state, on top of the federal check. |
| Is anything I enter uploaded anywhere? | N/A | No. The checker runs entirely in your browser; nothing you enter is sent to a server. |
Using last year's figure. The federal threshold has changed four times since 2022: $20,000/200 transactions through 2023, $5,000 with no transaction minimum for 2024 only, then back to $20,000/200 from 2025 on. A search result, a news article, or even an old bookmark can easily be reporting a figure that applied to a different tax year than the one you're checking.
Because they produce opposite answers at the boundary. The IRS's own wording is "exceeds $20,000" and "exceeds 200 transactions" — strictly greater than, not "at least." A seller paid exactly $20,000 across exactly 200 transactions has not crossed the federal threshold under either condition. A quick mental check that rounds "exceeds" up to "at least" gets this specific case wrong.
No — and this is the mistake most likely to produce a wrong answer for someone selling on several platforms. The threshold applies separately to each Third Party Settlement Organization (TPSO). $15,000 from eBay and $15,000 from Etsy in the same year does not combine into $30,000 for either platform's own reporting decision; each platform checks only what it itself paid you.
Only four states currently do: Maryland, Massachusetts, Vermont, and Virginia, each at $600 with no transaction-count minimum, independent of whichever federal figure applies that year. That is not the kind of fact most people carry into a manual check, and a state's own department-of-revenue page is easy to overlook if you're only checking the federal rule.
Nothing about the actual law changes either way — a platform still applies its own reporting obligation regardless of what you calculated. What changes is whether you're caught off guard: expecting no form and getting one in January, or assuming a form means taxable income was newly created when it was always reportable. Getting the estimate right ahead of time is about avoiding the surprise, not the obligation.