Annual Tax Planner for Online Sellers

Online selling introduces a tax concept that most people never encounter in traditional employment - cost of goods sold. The tax math works differently for product-based businesses: gross sales minus COGS equals gross profit, then gross profit minus operating expenses equals net taxable income. For a seller with $40,000 in gross sales, $15,000 in COGS (materials, wholesale purchases, packaging), and $8,000 in operating expenses (platform fees, shipping, advertising, software), the taxable income is $17,000 - less than half the top-line number. Every dollar of COGS that goes untracked is a dollar of extra tax paid.

Platform fees create a significant gap between what a customer pays and what a seller actually receives, and the gap varies meaningfully by platform. Etsy's combined fees (listing, transaction, payment processing, offsite ads) can total 10-13% of the sale price. Amazon's referral fees run 8-15% depending on category, plus FBA fees if using fulfillment. Shopify's transaction fees are lower (2.6-2.9% + $0.30) but come with a monthly subscription. The 1099-K from each platform reports the gross amount the customer paid - not what landed in the seller's account. A seller who received $20,000 in deposits might see a 1099-K showing $25,000. Tracking platform fees throughout the year documents the difference and supports the deduction.

Inventory management has direct tax implications that catch many sellers off guard. Unsold inventory at year-end is an asset on the books, not a deduction - meaning the $3,000 spent stocking up for holiday sales in November cannot be written off until those items sell. For sellers who buy in bulk to get better unit pricing, this creates a timing mismatch between cash outflow and tax deduction. Tracking purchases, sales, and remaining inventory throughout the year makes the year-end COGS calculation straightforward and ensures the distinction between sold and unsold goods is clear for Schedule C.