Quarterly estimated taxes: what craft vendors need to know before September 15

Spring and summer are usually behind you by mid-August, and a fair amount of income has already come in from a season of Markets and Festivals. If you sell as a sole proprietor or through most small-business setups, the IRS generally doesn't wait until next April to collect its share of that — it expects a payment four times a year, and the third one for 2026 is due September 15. That's exactly one month from now, and it's a good moment to talk about what quarterly estimated taxes actually are, whether you owe them, and how to use the season you've already had to get this payment right.

This is general information, not personalized tax advice — more on that at the end. But the shape of it is worth understanding even before you talk to a professional.

Why estimated taxes exist in the first place

A W-2 job has taxes withheld from every paycheck automatically, so by the time April rolls around, most of the bill is already paid. Self-employment income — including the money that comes out of a booth at a Show — doesn't have anyone withholding on your behalf. The IRS's answer to that is the estimated tax system: instead of one lump payment (or one lump surprise) at filing time, you pay roughly as you earn, in four installments across the year.

The general rule of thumb is that you're expected to make estimated payments if you'll owe $1,000 or more in tax for the year after subtracting withholding and credits. For most vendors doing this as a real source of income — not the rare weekend hobby table — that threshold gets crossed quickly, because self-employment income carries both regular income tax and self-employment tax (the vendor-side version of the Social Security and Medicare taxes a W-2 job would otherwise withhold).

The 2026 schedule

The IRS splits the year into four payment periods, and the due dates don't line up neatly with calendar quarters:

• Q1 — due April 15, 2026
• Q2 — due June 15, 2026
• Q3 — due September 15, 2026
• Q4 — due January 15, 2027

The September payment covers income from roughly June through August — in other words, a decent chunk of your summer season. If you had a strong run of Markets this summer, this is the payment where that income actually shows up.

Figuring out what to send

The IRS gives you a couple of accepted ways to land on a number without needing to predict the future exactly:

Match last year, roughly. Pay in, across the year, at least 100% of what you owed in total tax last year (110% if your income was higher — the IRS publishes the exact threshold each year, so check the current figure rather than assume). Hit that mark and you're generally protected from an underpayment penalty even if this year turns out to owe more.

Pay a share of what you'll actually owe this year. The alternative is paying at least 90% of your actual current-year tax liability across the four installments. This requires a real estimate of the year's income and expenses, which is harder to nail down mid-year but can mean paying less if this season is slower than last year's.

Most vendors find the "match last year" route the easier one to plan around, especially for the payments early in the year before the season's shape is clear. By September, though, you have real information: three-quarters of the year's Shows are done, your Tracker has actual take-home numbers instead of guesses, and this payment is a good checkpoint to true up against where the year is actually heading rather than just repeating a number from January.

What actually gets taxed

It's worth being precise about the number you're estimating tax on. It isn't your gross sales at the register — it's your net profit for tax purposes, which is your business income after your deductible business expenses (materials, booth fees, mileage, and the rest) come out. That's a different number from the take-home you track per Event (sales minus booth fee, travel, and other costs for that weekend), but the two are closely related: a season of solid take-home numbers is a good early signal that this year's tax bill is trending up from last year's, which is exactly the kind of thing worth flagging to whoever handles your taxes before the September payment, not after it.

How payments actually get made

The mechanics are straightforward once you know the amount: the IRS accepts estimated payments through its own online payment system, through EFTPS (the federal government's free payment system for scheduled tax payments), or by mailing a check with the payment voucher from Form 1040-ES. Any of these routes gets recorded against the right quarter as long as it's submitted by the deadline — the method matters less than making sure the payment actually lands on time, since a late one is treated the same as a missed one for penalty purposes.

Don't forget your state

Estimated taxes aren't only a federal thing. Most states with an income tax run a similar quarterly system, often on a similar (though not always identical) schedule, and it's easy to handle the federal payment and forget the state one sits right alongside it. If you sell in a state with income tax, check whether a state estimated payment is due around the same time.

Why this specific deadline is worth flagging now

Every quarterly deadline matters, but September 15 lands at a useful spot on a vendor's calendar: the bulk of spring and summer selling is done and counted, while the heavier fall and holiday stretch — often the biggest income months of the year for a lot of vendors — is still ahead. That makes it a natural moment to look at the year so far, sanity-check whether your estimated payments are keeping pace with what you're actually earning, and flag any real gap to your tax preparer while there's still a full quarter left to adjust the Q4 payment rather than getting blindsided in January.

The takeaway

If you're selling as a business, the IRS generally wants its share of that income four times a year, and the third 2026 installment is due September 15 — about a month from today. The two accepted approaches are paying roughly what you owed last year or estimating this year's actual liability, and by this point in the season you have real numbers to work with either way. The single best thing you can do before the deadline is turn your season's sales and expenses into an actual number and get it in front of whoever handles your taxes, rather than guessing and hoping it's close.

This article is general information for craft vendors, not personalized tax advice. Estimated tax rules, thresholds, and safe-harbor percentages can change, and your specific situation matters — confirm your numbers and deadlines with a qualified tax professional (a CPA or licensed tax preparer) before you pay.

The Tracker keeps each Event's sales and take-home in one place as the season happens, so by the time a quarterly deadline rolls around, you're handing your tax preparer real numbers instead of reconstructing a summer from memory. Artisans Almanac offers a 30-day free trial if you want this season's numbers organized before the next deadline hits.