How to Track Real Profit as a Reseller (Without Guessing)

Why “sell price minus buy price” isn’t profit

The fastest way to overestimate income in reselling is to ignore the “in-between” costs. A flip can look great at first glance—until you account for shipping labels, platform fees, packing materials, and the mileage you drove to source, pick up, or drop off the item.

If you’re not tracking these costs, you might feel busy and see money moving through your accounts, but your actual profit margin can be much lower than you think. Tracking real profit is what helps you decide: what to buy, what to skip, and which platforms are worth it.

The real profit formula for resellers

Here’s the simplest way to calculate true profit per item. You can copy/paste this into a spreadsheet, or use it as the foundation for your tracking app:

Costs you should include (even if they seem “small”)

• Platform fees: listing fees, final value fees, payment processing
• Shipping: postage, label costs, insurance, signature confirmation (if used)
• Packing supplies: boxes, tape, bubble wrap, polymailers, labels
• Improvements: repairs, replacement parts, cleaning supplies, refurb items
• Mileage/travel: sourcing trips, pickups, drop-offs (track miles and assign a cost method)
• Adjustments: returns, partial refunds, chargebacks, discounts

Important: Mileage rules and deductibility can vary by situation. Track trips consistently and consult a tax professional for your specific setup.

A simple item-by-item tracking system (easy to maintain)

The goal isn’t to create perfect accounting—it’s to build a repeatable system that captures the information that determines profit. The best approach is to track costs per item whenever possible, and track shared costs (like supplies) in a consistent way.

Step 1: Give every item a unique ID

Use something simple you can repeat: 2026-001, 2026-002, etc. This helps you attach expenses, notes, and sale details to the correct item.

Step 2: Capture the purchase details immediately

• Item name/description
• Purchase date
• Where purchased (store/city or “online”)
• Purchase cost (including tax)
• Condition notes (so you remember why you priced it a certain way)

Step 3: Add costs as you go

Every time you spend money on an item—repairs, parts, supplies—log it. Waiting until “later” is how expenses get lost. A simple rule: if you can’t attach a cost to an item, you can’t trust your profit number.

Step 4: Record selling details when it sells

• Sold date
• Sale price
• Platform (eBay, Facebook Marketplace, Etsy, in-person, etc.)
• Fees (platform + payment processing)
• Shipping cost (if you paid it)
• Any refunds/returns (if they happen)

Step 5: Review profit by category and by month

Item-level profit tells you what worked. Monthly totals tell you if you’re building a business or just moving money around. The best resellers use both views.

Example: profit on a single flip (real numbers)

Here’s a realistic example to show why tracking details matters:

If you only used “sell price minus buy cost,” you’d think you made $70. In reality, you made $32.95—still profitable, but a completely different margin. This is exactly why “real profit tracking” changes your buying decisions.

Common profit-tracking mistakes (and how to avoid them)

1) Ignoring fees until the end of the month

Fees are not “general overhead”—they’re part of each sale. Track them per item so you can compare platforms and pricing.

2) Forgetting supplies because they’re purchased in bulk

You don’t need perfection—just consistency. Assign a small per-order supply cost (like $1–$3), or track supply purchases monthly and allocate them across the number of orders.

3) Mixing inventory and personal spending

Separate accounts make tracking dramatically easier. Even if you keep one bank account, keep your reseller records separate so you can prove numbers later.

4) Not tracking “time and travel” in any way

Even if you’re not claiming mileage, tracking trips helps you understand sourcing efficiency. Some items look profitable until you realize you drove an hour each way to get them.

A weekly workflow you can stick with

The best system is the one you’ll actually maintain. Here’s a simple weekly routine that keeps your numbers accurate without becoming a second job:

1. As you buy: log purchase cost, source location, and item ID (30–60 seconds).
2. As you spend: add improvements and supplies tied to the item (10–20 seconds).
3. As you sell: record sale price, fees, shipping, and sold date (30–60 seconds).
4. Once per week: review what sold, check margins, and identify what to source more of (10 minutes).

Next step: make profit tracking easier

You can absolutely start with a spreadsheet—but as your inventory grows, the “little costs” become harder to track and your profit numbers get less reliable. A dedicated system helps you keep everything connected: purchases, mileage, improvements, and sales outcomes.

Recommended next guides: Mileage tracking for resellers • Reseller expenses checklist • Spreadsheet vs software