Free tool
What would one double-sale a week cost you?
Selling the same part twice is not a refund problem. It is a defect on your eBay account, and eBay does not care that your inventory is one-of-one. Put your numbers in.
3 channels
Your defect rate
1.2%
0%eBay limit 2%4%
You are under the line — but 9 cancellations in a month is all it takes to cross it. That is the whole margin.
- Double-sales a month
- 4.8
- Cancellations to cross two percent
- 9
- Refunded over twelve months
- $10,368
- Orders the rate is measured across
- 4,800
The two percent threshold and the twelve-month window are eBay's published US seller standards. The collision estimate is ours and deliberately conservative — 0.6% of orders for each place beyond the first. We do not know your sell-through, and a tool that guessed it would be inventing the number it exists to give you.
Why this is the number.
Cancelling an order because the part already sold counts as a transaction defect, and a US seller above two percent is moved to Below Standard. That brings higher fees and lower search placement — on every listing, not just the one that failed.
The trap is that recovering needs sales, and Below Standard is what removes them. Defects stay on the account for twelve months, so one bad quarter is felt for four.
It is also the one metric where a used-parts seller is measured against sellers who can simply post another one. You cannot replace a hundred-thousand-mile part with a five-hundred-thousand-mile part and call it the same thing — but the defect is identical either way.