Example scenario · illustrative, not a real seller
The buyer pays a fee at checkout. Your seller fee is another line. Before deducting both from yourself, check whose charge each one is.
What you’ll get
- Seller-only fee arithmetic with the shipping kept visible
- A labelled worked example, a visual process and an editable cost-stack scratchpad.
- A device-only action checklist and one next move: Map one shipping credit and label charge
A buyer fee is not automatically a seller deduction.
A buyer’s checkout total and your net sale are different views of the transaction. Mixing them can cause two opposite mistakes: deducting a buyer-paid charge from yourself, or forgetting shipping and other seller costs because the listing screen looks profitable.
Start with the dated official structure
Mercari’s official fee page, checked November 8, 2026 and marked updated October 23, 2026, describes a 10% seller fee on item price plus buyer-paid shipping under the structure effective January 6, 2025. It separately identifies a buyer-paid Buyer Protection fee of 3.6% on that same stated base.
Do not add that buyer-paid fee to your seller deductions. It can affect the buyer’s total spend, but a buyer’s fee is not automatically a seller fee. Historical listings and old screenshots can reflect a different structure; use the source and the actual listing details.
Keep three shipping questions separate
What is the buyer charged? What shipping amount, if any, is credited in the seller-side accounting? What label cost or shipping adjustment is actually charged to you? Read the settlement instead of assuming all three numbers are interchangeable.
For a buyer-paid prepaid-label example, the accounting may show a shipping credit and matching label charge. Enter each once. For seller-paid shipping, do not invent a buyer shipping credit. The calculator needs the cost pattern for your real transaction.
Rebuild one illustrative sale
Choose a $40 item and $6 buyer-paid shipping, with no buyer sales tax in this illustration. The published seller-fee basis is $46, so the seller fee is $4.60. This is arithmetic using the cited rate, not a market-price estimate.
Assume a matching $6 label cost, $12 acquisition and $1.50 packing. $46 − $4.60 − $6 − $12 − $1.50 leaves $21.90 before income tax and omitted costs. The $6 label is a chosen input, not a Mercari rate quote. Do not deduct the buyer’s 3.6% fee again.
Check what could change the result
The official page lists separate services and charges, including withdrawal choices and potential shipping adjustments. Do not spread an optional cash-out charge across every sale as though it were an unavoidable selling fee. Allocate an actual charge consistently if you use that service.
Weigh and measure the final packed parcel. A label suggestion is not permission to ignore dimensions or carrier requirements. Read current restrictions for batteries and other hazardous contents before listing, not after the sale.
Use the estimate to set a buying ceiling
Take the fee amount and actual costs to the sourcing ceiling. Reduce the sale scenario and increase a cost assumption to see how fragile the result is. This is sensitivity testing, not a forecast of a return rate or a guarantee a buyer will appear.
Keep the actual order and payout records after completion. A correct selling-fee percentage is only one line in a complete resale ledger.
Worked example · hypothetical, not a real seller
Seller-only fee arithmetic with the shipping kept visible
This uses the text’s hypothetical $40 item + $6 buyer-paid shipping, $12 stock, $6 label, $1.50 packing and the cited $4.60 seller-fee calculation. The label amount is chosen, not an official shipping quote.
$46.00 receipts − $12.00 acquisition − $12.10 other costs = $21.90 operating surplus before income tax and omitted labor/overhead. Other costs must include relevant fees, postage, packing, repairs and return exposure once each.
| Measure | Example value |
|---|---|
| Receipts ($) | 46 |
| All costs ($) | 24.1 |
| Surplus ($) | 21.9 |
Chosen example · edit the numbers
Cost-stack scratchpad
Illustrative inputs, not market benchmarks or an achieved outcome. Scratchpad values stay in tab memory, not saved by this application. Reload to reset.
Before the next transaction
With JavaScript and browser storage, only checked-step IDs can stay on this device. No buyer details or amounts are saved.
Should I deduct the buyer protection fee as another seller fee?
Not under the published current US structure cited here. Mercari identifies it as buyer-paid. Model the seller fee on item price plus buyer-paid shipping, then separately enter actual seller-paid shipping and other charges. Confirm the official terms for the listing.
Do this next · one concrete move
Map one shipping credit and label charge
Use the actual transaction pattern. Do not add a shipping credit you never receive, deduct a label twice or treat the buyer protection charge as another seller fee under the cited structure.
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