See what eBay keeps from a sale and what you receive. Fee rates are prefilled with eBay's standard rates for most categories and are editable, so you can match your own category.
eBay fee calculator
Prefilled with eBay's standard rate for most categories: 13.6% on sales up to $7,500 (2.35% on the part above) plus a per-order fee of $0.40 on orders over $10. Rates differ by category and account, so check eBay's fees page.
On a $60 item with $8 shipping, eBay's standard fee comes to about $9.65: 13.6% of $68 is $9.25, plus $0.40. The fee applies to the whole amount the buyer pays, not just the item.
That's the part sellers tend to miss: shipping you charge the buyer is inside the fee base, and so is sales tax where eBay collects it. If you enter shipping above, the calculator includes it.
The reverse box answers the other common question: what do I need to charge to end up with a set amount after fees? It divides your target plus the fixed fee by one minus the percentage.
Enter your item cost and what you pay to ship, and the calculator shows profit after costs. That's the number to compare across eBay, your own Shopify store and other marketplaces. To compare with a store, the Shopify profit margin calculator uses the same idea with payment fees and ad cost.