ROI Tracking for Resellers: From Purchase Price to Net Profit

Ask ten resellers what their average profit per sale is, and most will guess.

They’ll say “around 30%” or “depends on the item.”

But if you can’t track return on investment (ROI) precisely, you’re guessing your way through your business.

ROI tracking is what separates serious resellers from hobby sellers. It helps you see what’s working, what’s not, and where your money truly grows.

Let’s break down how to track ROI accurately from the moment you buy an item to the final profit in your bank account.

Why ROI Tracking Matters for Every Reseller

When you buy and sell dozens or hundreds of items, it’s easy to lose track of your real margins.

A product might sell fast, but after marketplace fees, shipping, and packaging, the actual profit could be far smaller than it looks.

Here’s why tracking ROI matters:

Avoid illusion profits: A $10 gain might look good until you realize you spent $8 on shipping and fees.
Find your winners: You’ll spot which SKUs give consistent 40–60% returns and which waste your time.
Plan reinvestments: Real ROI data helps you decide what to restock and what to drop.
Understand cash flow: You’ll know how much money is tied up in inventory versus what’s liquid.

Without ROI tracking, you’re driving blind.

The Basic ROI Formula (and What Most Sellers Miss)

Most resellers think ROI is simply:

ROI = (Profit ÷ Cost) × 100

That’s true, but only if you define profit correctly.

Let’s expand it.

Profit = Sale Price – (Product Cost + Platform Fees + Shipping + Packaging + Taxes)

Then plug that into the ROI formula.

Example:

Product Cost: $20
Sale Price: $60
Platform Fees: $9 (15%)
Shipping: $6
Packaging: $1

Profit = 60 – (20 + 9 + 6 + 1) = $24

ROI = (24 ÷ 20) × 100 = 120% ROI

That’s your true return. Every $1 you spent made $1.20 in profit.

What to Include in ROI Calculations

Many resellers undercount costs, which inflates ROI.

Here’s a checklist to make your tracking airtight.

Cost Type	Description	Example
Product Cost	What you paid to acquire the item	Walmart clearance item for $12
Marketplace Fees	eBay final value, PayPal, or Amazon referral fees	$3.60 (eBay 12%)
Shipping	Label cost + supplies	$5 USPS
Packaging	Boxes, tape, bubble wrap	$1 per order
Taxes	Sales or import taxes on purchase	$1.20
Refunds / Returns	Subtract total refunds or write-offs	One item returned at full refund
Promotions / Ads	Paid boosts or promoted listings	$2 ad cost

If you skip any of these, your ROI reports will lie.

Step-by-Step: How to Track ROI for Every Item

Let’s build a workflow that works for both small and large inventories.

Step 1: Record the Purchase

When you buy, immediately log the item name, cost, and SKU.
Include quantity and supplier (e.g., “Target clearance,” “Local thrift”).
If using spreadsheets, columns should include:
SKU | Product | Buy Price | Tax | Fees | Shipping | Sale Price | Profit | ROI

Step 2: Log the Sale

When the item sells, fill in sale price and all associated costs.
Calculate net profit and ROI automatically with formulas.
Add a “Status” column to mark Sold or Unsold.

Step 3: Review Monthly Performance

Sort by ROI descending.
Highlight top-performing SKUs (50%+ ROI).
Flag poor performers (<10% ROI or losses).
Decide which items to reinvest in and which to avoid.

Using ROI Data to Make Smarter Decisions

Tracking ROI isn’t just for reports, it’s for better decisions.

Here’s how pros use the data.

Insight	What It Tells You	Example Action
Top 20% of SKUs = 80% of profit	Focus on what works	Source more similar items
Low ROI, high volume items	High effort, low reward	Reduce sourcing time here
High ROI, slow movers	Great margins but low turnover	List on multiple marketplaces
Negative ROI	Hidden costs killing the margin	Reevaluate pricing or shipping strategy

Once you identify patterns, you can scale confidently without guessing.

Common ROI Tracking Mistakes (and Fixes)

Mistake	Why It Hurts	Fix
Only tracking sale price and cost	Hides fees and shipping	Include all costs in calculation
Using overall ROI instead of per-SKU	Masks low performers	Track each product separately
Forgetting refunds	Inflates real ROI	Subtract refunded sales
Mixing buy price with total quantity	Miscalculates ROI per unit	Divide total cost by units
Ignoring time costs	Overestimates ROI	Estimate time per task to know efficiency

Small mistakes compound fast. Accurate ROI helps you scale cleanly.

Example: Quick ROI Tracking Template

SKU	Product	Buy Price	Sale Price	Fees	Shipping	Profit	ROI
TOY-001	LEGO Star Wars 75304	$35	$85	$10	$8	$32	91%
BOOK-004	Cook Like a Pro	$3	$18	$2.50	$3.50	$9	300%
FIG-009	Funko Pop: Spider-Man	$12	$24	$3.50	$5	$3.50	29%

This kind of breakdown instantly shows what to double down on.

The Philosophy: Simplify, Don’t Overcomplicate

Good ROI tracking doesn’t need to be fancy.

The best system is the one you’ll actually use every day.

Whether it’s a Google Sheet or an app that automates these fields, the goal is the same:

Track every product from purchase to sale
Include every cost that affects profit
Review and adjust based on data, not instinct

Once ROI becomes a habit, every sourcing decision becomes sharper.

FAQs

Q: How often should I calculate ROI?

Weekly or bi-weekly. It’s easier to correct mistakes before they pile up.

Q: Should I include time in ROI?

Not in the formula, but track it separately. If a $10 profit takes 30 minutes, your effective hourly rate is $20/hour, that’s a hidden insight.

Q: What’s a good ROI for resellers?

For used items or collectibles, aim for 100%+. For retail arbitrage, 30–60% is solid.

Actionable Takeaways

✅ Always calculate ROI at the SKU level.

✅ Include all fees, shipping, and packaging in your costs.

✅ Review your ROI data monthly to guide sourcing.

✅ Focus on high-ROI, repeatable products.

✅ Use tools or templates that make ROI tracking fast and accurate.

ROI isn’t about math, it’s about clarity.

When you know exactly where your money grows, you’ll scale faster, spend smarter, and reinvest with confidence.