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Whatnot Schedule C Calculator
Plug in your year-end revenue, COGS, fees, and expenses. You'll see Schedule C net profit, your self-employment tax estimate, and a rough quarterly payment. Maps to IRS Schedule C lines.
No credit card. $19/mo if you keep going.
Inputs (full year)
Schedule C breakdown
| Line 1 — Gross receipts | $25,000 |
| Line 4 — COGS | −$10,000 |
| Line 5 — Gross profit | $15,000 |
| Line 28 — Total expenses (fees + shipping + other) | −$5,000 |
| Line 31 — Net profit | $10,000 |
| Self-employment tax (~14.13%) | $1,412.96 |
| ↳ Half is deductible above-the-line | −$706.48 |
Net margin
40.0%
of revenue, after all costs
Quarterly est. (SE only)
$353
income tax extra, see notes
Self-employment tax = 15.3% on 92.35% of Schedule C net profit (SS portion caps at $176,100 in 2026; Medicare portion uncapped). Federal income tax depends on your total household income, filing status, and other deductions. Talk to a CPA for filing.
How the math works
- Gross receipts = your 1099-K total from Whatnot
- COGS= what you paid for the inventory you sold this year. Whatnot doesn't track this. You do.
- Total expenses = Whatnot fees + seller-paid shipping + boost spend + supplies + mileage + anything else legitimately business-related
- Net profit = Gross profit minus expenses. This is line 31 on Schedule C and what flows to your 1040.
- SE tax = 15.3% on 92.35% of net profit. SS portion caps at $176,100 combined earnings in 2026; Medicare is uncapped.
Want this number from real data?
Upload your weekly CSVs. We compute COGS, fees, and shipping per item and hand you a Schedule C-ready CSV at year-end.
Embed this calculator on your site
Free to use on any seller blog, Discord landing page, or guide. Drop the snippet anywhere HTML is allowed.
<iframe
src="https://aftershows.co/embed/whatnot-schedule-c-calculator"
width="100%"
height="920"
style="border:1px solid #e4e4e7;border-radius:8px;max-width:760px"
title="Whatnot Schedule C Calculator"
loading="lazy"
></iframe>Default height is 920px. Adjust if your site is narrower than 760px. A small “Powered by Aftershows” link sits at the bottom.
FAQ
What is Schedule C?⌄
Schedule C is the IRS form for reporting profit or loss from a sole-proprietor business. If you sell on Whatnot as a business (not a hobby), your activity goes on Schedule C. Net profit (line 31) flows to your 1040 and is subject to both income tax and self-employment tax.
How is self-employment tax calculated?⌄
SE tax is 15.3% on 92.35% of your Schedule C net profit. That works out to roughly 14.13% of net profit. The Social Security portion (12.4%) caps at $176,100 of combined earnings in 2026; the Medicare portion (2.9%) is uncapped. Half of SE tax is deductible above the line on your 1040.
What expenses are deductible on Schedule C?⌄
Whatnot commission and payment processing (Line 27a Other expenses), seller-paid shipping (Line 27a), boost or promotion spend (Line 8 Advertising), supplies and packaging (Line 22), business mileage (Line 9), home office (Line 30 if eligible). COGS goes in Part III (Lines 36-42).
Does this replace a CPA?⌄
No. This estimates net profit and SE tax. Federal income tax depends on your full household income, filing status, other deductions, and credits. Use this for ballpark planning and quarterly estimates. File with a CPA or qualified tax software.
Year-end tax prep, automated.
Stop estimating. Generate a Schedule C-ready CSV.
Upload your weekly CSVs through the year. We track COGS per item, tag every fee and shipping cost, and export the numbers your CPA (or you) drops onto Schedule C.
No credit card. $19/mo if you keep going. Cancel anytime.
Related reading
Whatnot taxes 101
1099-K, Schedule C, deductibles, year-end checklist.
Whatnot fees calculator
Per-sale fee math: commission, processing, net payout, true profit.
Whatnot profit calculator
Estimate true profit per show after fees, shipping, boost, and COGS.
Reseller bookkeeping
What to track, how to track it, what to hand your CPA at year-end.