Two numbers decide most retail-arbitrage buys: ROI (how much you make back on what you spend) and BSR (how fast a product sells). New sellers want a single magic threshold for each. The honest answer is "it depends" — but there are sensible benchmarks, and once you understand what drives them you can set your own.
What's a good ROI?
ROI is your net profit divided by what the unit cost you. Most UK retail-arbitrage sellers aim for a minimum of around 30% ROI, and pair it with a minimum cash profit per unit — often £3–£4 — so that small wins are still worth the handling time.
Why two thresholds? Because percentages lie at the extremes. A 50% ROI on a £2 item is just £1 profit — not worth the pick, pack and shelf space. A 25% ROI on a £40 item is £10, which might be very worth it. Use ROI and an absolute profit floor together.
Your right number depends on:
- How fast it sells — you can accept lower ROI on something that flips in days, because your cash recycles quickly.
- Competition — more FBA sellers on a listing means more price pressure, so demand a bigger cushion.
- Cash flow — if cash is tight, higher ROI and faster turnover matter more than total profit.
What's a good BSR?
Best Sellers Rank shows how well a product sells in its category: lower is better (#1 is the best seller). The trap is comparing BSR across categories — a BSR of 20,000 might be a fast seller in a huge category and a slow one in a small category. Always read BSR relative to its category, and ideally look at the Keepa price and BSR history, not just today's number, because a single snapshot can be misleading.
As a very rough orientation for big UK categories, a BSR in the top 1–2% of the category usually means healthy, regular sales; deep into the long tail means slow. But the reliable signal isn't the raw rank — it's estimated monthly sales and a BSR chart that drops regularly (each drop is roughly a sale). If a product sells only a handful of units a month and several FBA sellers share it, even a great ROI can mean your stock sits for months.
Putting ROI and BSR together
The buy/skip decision is really a balance of three things: enough margin (ROI + cash profit), enough demand (BSR / sales velocity), and not too much competition (FBA seller count). A product that's strong on all three is a clear buy. Strong on margin but weak on demand is a cash trap. Strong on demand but thin on margin is a volume play only worth it if you can buy a lot.
| Signal | Rough "green light" | Why |
|---|---|---|
| ROI | ~30%+ | Cushion for price dips and returns |
| Cash profit/unit | ~£3–£4+ | Makes the handling worth it |
| BSR / demand | Top ~1–2% of category, regular sales | Stock actually moves |
| FBA sellers | Few | Less price pressure on the Buy Box |
These are starting points, not rules — set your own based on your cash flow and goals. (And remember the 2026 fee changes affect the profit half of the equation.)
Don't work it out by hand
Calculating ROI after UK fees and VAT, then cross-checking BSR and competition, is slow and error-prone on a shop floor. Our free UK FBA calculator gives you net profit, ROI and margin instantly, and shows the MAX PAY price — the most you can pay and still hit your target ROI. Axivelo does the same on a barcode scan and surfaces Keepa-style demand and competition signals next to the profit, so you can apply your thresholds in seconds. For the mechanics behind the fees, see Amazon FBA fees in the UK, explained.
See ROI, MAX PAY and demand per scan
The free UK FBA calculator shows net profit, ROI, margin and the most you should pay. Axivelo adds demand and competition on a barcode scan.
Open the free FBA calculatorFAQ
What ROI should I aim for on Amazon FBA?
Many UK retail-arbitrage sellers use a minimum of around 30% ROI plus a minimum cash profit of about £3–£4 per unit. Faster-selling items can justify lower ROI; slow or competitive ones need more.
What is a good BSR to sell on Amazon UK?
Lower is better, and it's only meaningful within the same category. As a rough guide, the top 1–2% of a category usually sells well, but the more reliable signal is estimated monthly sales and a BSR history that drops regularly.
Is a high BSR good or bad?
A high BSR number is bad — it means the item ranks low and sells slowly. A low BSR (closer to #1) means it sells fast.
UK Amazon FBA seller and founder of Axivelo, a barcode scanner that shows profit, ROI, MAX PAY and demand on every in-store scan.