How to Track Reselling Sales, Inventory and Profit

To know whether reselling is actually making you money, and to file your taxes correctly, you need a record of what each item cost and what it brought in after fees and shipping. This guide covers what the IRS says to keep, a simple per-item spreadsheet layout, how to pull reports from eBay and StockX, and what a few tracking apps cost.

This is general information for US resellers, not tax advice. Tax rules change, so check the IRS pages linked below or ask a tax professional.

Why tracking matters#

• Taxes. Marketplaces report what they paid you, not what you made. A Form 1099-K shows gross payments, so without your purchase costs you can't show the difference. Our guide to reseller taxes and 1099-K forms explains the forms.
• Real profit. The sale price isn't what you keep. Fees, shipping, the sales tax you paid when buying and the supplies you used all come out of it. Tracking each item shows which ones were worth it.
• Cash flow. Knowing what's unsold, and for how long, shows how much money is tied up.

What the IRS says to keep#

The IRS doesn't require a particular system. Its recordkeeping page says you can use any system that clearly shows your income and expenses, and that electronic records count as long as they meet the same rules as paper ones.

For purchases, which for a reseller means the items you buy to sell, records should show who you paid, the amount, proof of payment, the date and a description of the item. Receipts, card statements, invoices and electronic transfer records all work as proof. Keep the same kind of records for expenses, such as supplies and software, and for sales.

IRS Publication 583 calls inventory "any item you buy and resell to customers," and says to keep your business account separate from your personal checking account.

Cost of goods sold#

If you buy goods to sell, Publication 334 says you can deduct the cost of goods sold on Schedule C, and that you must value your inventory at the beginning and end of each tax year. In short:

• start with your inventory at the beginning of the year;
• add what you bought for resale, including shipping you paid to get the items (freight-in), at the prices you actually paid;
• remove anything you took out of inventory for personal use;
• subtract your inventory at the end of the year.

That's why a year-end count of unsold items matters.

How long to keep records#

IRS Topic 305 says generally 3 years from when you file, 6 years if you leave out a substantial amount of income, and with no limit for a fraudulent return or no return. Records for items you still hold should be kept until the period ends for the year you sell them.

What to track for each item#

A spreadsheet with one row per item covers most resellers. We started in Excel, later moved to Google Sheets, and still track this way. These are the columns we suggest:

A few tips:

• Use formulas for sales tax, fees and shipping. In our experience, those three are what quietly eat into margins, so let the sheet calculate them. A fee cell, for example, can multiply the sale total by the platform's fee rate and add any per-order fee. eBay's fee table says its fee is figured on the total, including shipping and sales tax.
• Mark items you keep as "kept" rather than deleting them, since personal-use items come out of your purchases.
• Add a second tab for expenses that aren't tied to one item, such as supplies bought in bulk, software or a bot license.
• Store the receipt (a photo or PDF) with a link or file name in the row.

To check one item's numbers quickly, the resale profit calculator does the same math.

Using platform reports#

Platforms already record your sales, fees and payouts, so export them instead of retyping.

• eBay. In Seller Hub, the Payments tab has a transaction report: a CSV for any date range with order and payout IDs, gross and net amounts, final value and other fees, shipping label charges, refunds and adjustments. eBay also offers monthly PDF financial statements, kept for 10 years, and monthly tax invoices for seller fees. Seller Hub Reports can also pull orders reports for 1 to 90 days on a schedule.
• StockX. StockX said in September 2025 that sellers can export sales history as a CSV covering the past two years from the sales history page in StockX Pro, its seller tool. The file arrives by email.

Match each sale back to your spreadsheet by order ID. The reports don't know what you paid for the item, so your own purchase records still matter. Our guide to StockX, GOAT and eBay fees explains what each fee line means.

Inventory and bookkeeping apps#

Reseller tracking apps import sales from connected marketplaces, match them to your inventory and build reports such as profit and loss. Two examples, in alphabetical order, with prices as listed in October 2026. Naming them isn't a recommendation.

• Flipwise describes itself as built for the business side of eBay selling. Its pricing page is based on store size: free up to 24 listings for new members, $19.99 a month for 100 to 499 listings, and tiers on its help center from $9.99 to $69.99. Sales from other platforms can be added by hand. It lists a 7-day money-back guarantee.
• My Reseller Genie lists Basic at $11.99, Premium at $16.99 and Ultimate at $22.99 a month, with integrations for eBay, Poshmark, Mercari, Whatnot, Etsy, Depop and Vinted plus bank accounts, mileage tracking, and profit and loss and inventory reports. It lists a 14-day money-back guarantee.

Neither page we read lists a StockX integration, so check how an app handles every platform you sell on before you pay.

We chose to keep our own records in a spreadsheet on a platform we already trust, mainly to keep control of our data. That's a preference, not a verdict on apps; plenty of sellers use them to save typing.

How often to update#

Records only help if they're current. In our experience that means updating often, sometimes several times a day when sales are moving. As a minimum:

• When you buy: add the row and save the receipt the same day.
• Weekly: export platform sales and fill in sold items.
• Monthly: compare your records with the payouts that reached your bank.
• At year end: count unsold inventory for the cost of goods sold calculation.

Good records also make pricing easier, since you can see what similar items actually netted. See how to price eBay listings.

Mileage and other costs#

If you drive to stores or the post office for the business, Publication 334 covers deducting car expenses by the standard mileage rate or actual expenses. Check the current rate on IRS.gov.

If you're deciding whether to set up a separate business entity, our guide to whether resellers need an LLC explains what changes and what doesn't.

Tracking tools on OOSClub#

OOSClub lists reseller tools with their prices and features from their own pages. Browse them on the tools hub.