How to Actually Calculate Your eBay Profit (Most Sellers Get This Wrong)

You sold an item for £30. Great, right? Not necessarily. That £30 is revenue, not profit, and the gap between the two is where most eBay sellers quietly lose money without ever noticing.

Here's every cost that comes out of that £30 before you see a penny of actual profit.

eBay's cut

eBay charges a final value fee, typically around 12-13% of the total sale price (including postage you charged the buyer), plus a small fixed fee per order. On a £30 sale, that's roughly £3.80-£4.20 gone before anything else.

Payment processing

If you're not on eBay's managed payments default rate, or if you use a separate processor, there's usually another percentage-based fee here too. Easy to forget because it's not itemised the way the final value fee is.

VAT, if you're registered

If you're VAT registered, 20% of your sale price effectively belongs to HMRC, not you. Sellers who forget to account for this often think they're profitable right up until their VAT return.

Packaging and postage supplies

Boxes, padded envelopes, tape, labels. Individually pennies, but they add up to real money across hundreds of orders a month, and they're the cost most sellers never actually track per-item.

Storage

If you're paying for storage space, even just a spare room's worth of shelving, there's a real cost per item sitting there, even if it feels "free" because you already own the space.

Advertising

Promoted Listings fees are a percentage of the sale price for any order that came through a promoted listing. If you're running ads, this is often the single most underestimated cost on the list.

Your actual cost price

Obvious, but worth stating plainly: your cost price needs to be the landed cost, including what you paid the supplier, shipping to get it to you, and any import duties, not just the headline unit price.

So what's left?

Take that £30 sale. Subtract the eBay fee (£3.80), payment processing (maybe £0.30), VAT (£5.00 if registered), packaging (£1.20), storage (£0.30), advertising (£0.50), and your cost price (£10). What's left is your actual profit: £8.90, not £30. Under 30% margin, not the 100% your revenue number might have implied.

Why most sellers get this wrong

Not because they're bad at maths. Because nobody adds all seven of these up in one place, every time, for every listing, before it goes live. It's tedious to track by hand across hundreds of SKUs, so most sellers either skip it entirely or estimate loosely, and loose estimates are exactly how a "profitable" shop quietly runs at a loss on its best-selling item.

This is the entire reason Seller OS's Profit Calculator exists: put in your real costs once, and every price gets checked against every one of these seven line items automatically, before you ever publish a listing that would lose you money.