Guide · Inventory & profit tracking
How to Track Reseller Inventory and Profit
How to track reseller inventory and profit, in one system: one row per item in a spreadsheet, from the day you buy it to the day it sells, with cost, fees, shipping and profit on every row. If you can filter that sheet by platform, month and status, you know exactly what you made, what is still sitting unsold, and what your 1099-K will show before tax season starts.
Fees checked October 2026 · US fee schedule
The one-row-per-item system
Forget separate notebooks, photos of receipts and platform dashboards you check once a year. The system that works for resellers at any scale is a single spreadsheet — or a simple inventory app using the same columns — where every item gets exactly one row the day you buy it, and that row is updated as the item moves. One row per item means nothing is double-counted, nothing is forgotten, and your profit is a sum, not a guess.
| Column | What to enter |
|---|---|
| Date bought | The day you paid for the item |
| Item + location | What it is, plus where it is stored (bin, shelf, box) |
| Source | Thrift store, estate sale, retail arbitrage, wholesale |
| Cost | What you paid, including any tax on the purchase |
| List price | What you listed it for |
| Platform | eBay, Mercari, Depop, Poshmark, and so on |
| Sale price | What the buyer actually paid for the item |
| Shipping charged | What the buyer paid you for shipping ($0 if free shipping) |
| Fees | Platform fees on that sale, from the payout report |
| Actual shipping | What you actually paid the carrier, plus packaging |
| Status | Sourced, Listed, Sold, Shipped, Returned, Disposed |
| Profit | Formula (see below) — never typed by hand |
Location is the column most resellers skip and most regret skipping. When an item sells six months after you listed it, “blue bin, second shelf” is the difference between shipping same-day and tearing the garage apart. Give every storage spot a short code and use it consistently.
The profit formula for every row
Profit = sale price + shipping charged − fees − item cost − actual shipping. Margin = profit ÷ sale price. That formula is the same one our calculators use, and it is worth memorizing: fees are charged on the shipping you charge the buyer, so shipping belongs on both sides of the equation. A worked row from the reseller profit calculator:
| Sale price | Shipping charged | Fees (eBay) | Item cost | Actual shipping | Profit |
|---|---|---|---|---|---|
| $50.00 | $0.00 | $7.20 | $10.00 | $5.00 | $27.80 |
Enter fees from the platform’s payout or fee report after the sale, not from memory — the eBay fee calculator and its siblings estimate fees before you list, but the report is the exact number for your records. For offers, check the offer calculator before accepting: a $40 offer on a $50 listing changes the whole row.
Monthly reconciliation: the habit that pays
Once a month, reconcile: filter the sheet to last month’s sold rows, add up sale prices, fees and shipping, and compare the totals to each platform’s payout report. They should match within a few dollars — refunds and fee adjustments explain small differences, and your notes column should say why. This monthly check is what turns a spreadsheet into a tax record: when the 1099-K guide thresholds come into view, you already know your gross per platform, and you can prove every deduction behind it.
Reconciliation also exposes dead stock. Filter to “Listed” rows older than 90 days and you have your markdown list: items that need a price cut, a bundle (see the bundle profit calculator) or a move to a different platform. Inventory that never sells is not an asset — it is rent on shelf space.
Profit views: per item, per platform, per month
The same sheet answers three different questions. Per item: sort by profit to find your best and worst sellers — that tells you what to source more of. Per platform: sum profit by platform to see where your time actually pays; a platform with high fees but high prices can still beat a cheap platform with low prices, and the lowest fee marketplace ranking shows why fees alone do not decide it. Per month: sum profit by sale month to see seasonality and whether the business is growing. The margin calculator helps you set targets for each view — the margin guide benchmarks (40–60% after fees) are a good starting point.
5 mistakes that break inventory tracking
- Logging cost when you sell, not when you buy. Receipts fade; log the cost the day the item comes home.
- Forgetting fees on shipping. Platforms charge fees on the shipping you charge — the shipping guide explains the math.
- Typing profit by hand. One typo hides in a total for months; always use a formula.
- Ignoring returns. A returned row keeps its cost and shipping loss — the return cost calculator quantifies it.
- Mixing personal and business items. Keep personal purchases off the sheet entirely, or your profit totals mean nothing.
Frequently Asked Questions
What is the best way to track reseller inventory?
A single spreadsheet with one row per item — cost, list price, platform, sale price, shipping charged, fees, actual shipping and profit — updated from purchase to sale. It scales from a dozen items to thousands without new software.
Do I need inventory software to resell?
Not at first. A spreadsheet covers most resellers; software earns its cost when you cross into hundreds of active listings, multi-platform syncing, or need barcode scanning for a warehouse.
How do I track profit per platform?
Filter your sheet by platform and sum the profit column. Compare that to each platform’s payout report monthly — the two should agree within refunds and fee adjustments.
What should I do with unsold inventory?
Filter listed items older than 90 days and act: cut the price, bundle them, move them to another platform, or donate and record the disposal. Unsold stock is shelf rent, not wealth.
How does inventory tracking help with taxes?
It proves your costs. A 1099-K shows gross payments; your sheet shows the fees, item costs and shipping behind that gross number, which is what turns gross into taxable profit. See the 1099-K guide.
Related tools & resources
- Reseller profit calculator — profit, margin and ROI per sale
- Margin calculator — margin, markup and ROI
- Offer calculator — profit if you accept an offer
- Bundle profit calculator — multi-item bundle pricing
- Return cost calculator — what returns really cost
- Reseller taxes: 1099-K explained — gross vs profit, not tax advice
- How to price items to make a profit — the fee-proof formula
- Lowest fee marketplace — all platforms ranked
Estimate only — fees checked October 2026. Platform names are trademarks of their owners; we are not affiliated with them. See our methodology for how fees are verified.