revaMargin of Safety (Reselling)
The cushion that keeps a flip profitable when the sale price, the fee or the buyer does not go your way.
- Margin of safety = your maximum buy price minus your actual buy price, in zł or as a percentage of the maximum.
- The maximum buy price itself comes from the maxbuy calculator: expected sale price, costs, profit floor and ROI floor.
- It protects against a sale landing at fast-sell instead of fair value, a not-as-described return, or a slower-than-expected sale.
- On OLX an accepted return goes back at the seller's cost; on Vinted a SNAD refund covers the item price, Buyer Protection fee and original shipping.
- Size the buffer to category risk — bigger for electronics and branded items with fake risk, smaller for stable categories — there's no universal percentage.
Margin of safety is the room between what you paid for an item and the price at which buying it would have stopped making sense. The bigger the gap, the more wrong you can be about the sale price, the wait, or a return, and still come out ahead — a core idea in the inventory management guide. This page covers the formula, a worked example, what the buffer actually protects against, and how to size it by category risk.
The formula
The max buy price itself is not a guess — it comes from working backwards from an expected sale price, delivery, prep costs, a minimum acceptable profit and a minimum acceptable ROI, the same inputs the max buy price calculator uses. Margin of safety only means something once that ceiling is set; skip it and "safety" is just a feeling.
Example in zł
Say a jacket's comparable asks form a ladder like the one below, and your max buy price — after fees, delivery and a 30 zł profit floor — comes out at 80 zł against a fast-sell level of 120 zł.
Say you actually pay 55 zł: your margin of safety is 80 − 55 = 25 zł, or 31% of the maximum. Say instead you pay 75 zł for the same item — the buffer shrinks to 5 zł, barely enough to absorb a single unexpected cost.
What the buffer protects against
A margin of safety isn't padding for its own sake — it exists because specific things can go wrong between buying and getting paid:
- The sale lands below plan. reva's price ladder puts fast sell near the cheapest quarter of comparable asks and fair value at the median of comparables that left the market — an estimate, not a guarantee of where your item will actually land.
- A not-as-described return. On OLX, an accepted Pakiet Ochronny claim sends the item back to you via Zwroty OLX at your cost as the seller, and the buyer is refunded the price, delivery and the Pakiet Ochronny fee. On Vinted, a SNAD return refunds the buyer the item price, the Buyer Protection fee and the original shipping — money that comes out of what you were paid.
- A slower sale than planned. Cash tied up longer than expected has its own cost — see opportunity cost for how to think about it.
Sizing the buffer by category risk
There's no published rule of thumb for resellers to copy here, so treat this as a method rather than a number to memorise:
- Wider buffer: electronics and branded items with meaningful fake risk, categories where you have few comparable sales to trust, anything you haven't sold before.
- Narrower buffer: stable, easy-to-verify categories you've sold repeatedly, items where condition is simple to confirm before you buy.
- Check how many genuine comparables you found before trusting the fair-value estimate
- Widen the buffer for anything with known counterfeit risk
- Widen the buffer for a first purchase in an unfamiliar category
- Narrow the buffer only for items you've resold with predictable outcomes before
Related terms
Margin of safety sits next to a handful of terms worth knowing alongside it. Fair market value is what the fair-value level in the ladder is estimating, and evaluating a deal covers how far you can safely push a buy price before it turns bad.
The broader picture of stock risk is in reselling risk; this page does not repeat that page's FAQ on the absolute maximum you should ever pay.
Frequently asked questions
What is a margin of safety when buying items to resell?
How big should a reseller's margin of safety be?
Is margin of safety the same as profit margin?
Sources
- Vinted UK help: Returning an item checked 13 Sept 2026
- OLX: Annex 8, Pakiet Ochronny (effective 27 Apr 2026) checked 13 Sept 2026
See price estimates on live finds
This calculator needs your inputs. Scout estimates fair value, a fast-sell price and demand for the finds it shows you. Estimates, not guarantees.
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