You don’t need a spreadsheet to know if a resale is worth it — but you do need the right formula and honest inputs. This guide explains exactly how our resale value calculator works, so you can check its numbers or do the maths on the back of a receipt.
Start with the right sale price
Every calculation depends on one number: the price a buyer will actually pay. Not your listing price, not the highest sale you’ve seen, and not the price new.
- Base it on recent sold prices for the same item in similar condition.
- Use the lower middle of the range, not the top.
- On Vinted and Poshmark, expect offers — use the price you’d accept.
If that number is wrong, every figure below is wrong too.
1. Proceeds — what you’d keep
Start with what reaches your pocket after the marketplace and the post office have taken their share:
Proceeds = sale price + postage the buyer pays you − marketplace fees − your postage cost − other costs
This is the only number that matters if you’re selling something you already own. There’s no “profit” in the reseller sense, because you didn’t buy it to resell.
Example: You sell a jacket you own on eBay UK as a private seller for £30. The buyer pays £3.50 postage, which costs you £3.20 to send, and you spend £1 on a mailing bag. eBay charges UK private sellers no final value fee on domestic sales.
Proceeds = £30 + £3.50 − £0 − £3.20 − £1 = £29.30
2. Profit
If you bought the item to resell, take off what you paid:
Profit = proceeds − purchase price
Example: You buy a jumper for £6 and sell it on Vinted for £28. Vinted charges private sellers no selling fee and the buyer pays postage. You spend £1 on a mailing bag.
Proceeds = £28 − £1 = £27. Profit = £27 − £6 = £21.
3. ROI (return on investment)
ROI shows how hard your money worked:
ROI = profit ÷ (purchase price + other costs) × 100
Example: £21 ÷ (£6 + £1) × 100 = 300%. You got your £7 back and made three times that again.
ROI only makes sense when you’ve spent something. If an item cost you nothing — say you were given it — ROI is “infinite”, which isn’t a useful number. Our calculator shows proceeds instead in that case.
4. Profit margin
Margin shows what share of the sale price you kept:
Margin = profit ÷ sale price × 100
Example: £21 ÷ £28 × 100 = 75%.
Margin helps compare items at different prices: a 75% margin on a £28 item and a 20% margin on a £200 camera tell you very different stories about risk.
5. Break-even price
The lowest sale price that covers every cost. It’s the price at which profit is exactly zero.
With percentage fees this isn’t a simple subtraction, because fees change as the price changes. On a marketplace that takes 13.6% plus 40p per order, you need to sell for noticeably more than your costs just to stand still.
If your expected sale price is close to break-even, the item is risky — a small price drop, a return or an unexpected cost wipes out the profit. And if fees are 100% or more (an unrealistic custom fee, say), no price can break even — the calculator tells you so.
6. Maximum buy price
The most useful number at the till. To double your money (100% ROI):
Max buy price = (what you’ll receive after fees and postage) ÷ 2 − other costs
Example: If you’ll receive £28 after fees and postage and have £1 of other costs, the most you should pay is £28 ÷ 2 − £1 = £13. If the tag says £15, haggle or walk away.
Fees that depend on the marketplace
Fees are where most mental maths goes wrong:
- Vinted (UK private sellers): no selling fee — the buyer pays Buyer Protection on top.
- eBay UK private sellers: no final value fee on domestic sales.
- eBay UK business sellers: a category-based percentage of item + postage, plus a per-order fee, a 0.35% regulatory fee and VAT on fees.
- eBay US and Depop US: fees are calculated on the total the buyer pays, including sales tax — even though that tax isn’t your money.
The fees comparison has the details and official sources.
Costs resellers forget
- Mailing bags, boxes, tape and labels
- Washing, dry cleaning, de-bobbling and repairs
- Travel to shops and car boots — petrol, parking, bus fares, entry fees
- Paid promotion (Vinted Bumps, eBay promoted listings, Depop boosts)
- Returns, and items that never sell
- Your time: photographing, listing, answering questions, packing and posting
None of the formulas above include your time or income tax. If you resell regularly in the UK, read Do I pay tax on reselling?.
Rules of thumb
- £10+ profit and 100%+ ROI is a common minimum for clothing.
- Cheap items need to sell fast or be bundled — your time is a cost.
- Higher-value items can work at lower ROI if the profit is large and they sell reliably.
- Be honest with the inputs. An optimistic sale price produces an optimistic verdict.
Skip the maths and use the calculator — it does all of this as you type, for both selling what you own and buying to resell.
