How to Read a Keepa Chart for Retail Arbitrage (2026 Guide)
What every line on the Keepa chart means, how to spot a price spike vs a real price, and the 30-second chart check that prevents the most expensive mistake in retail arbitrage.
What Each Line on a Keepa Chart Means
A Keepa chart has multiple colored lines on two axes — price on the left, BSR on the right. For retail arbitrage, you need to read two lines fluently: the Buy Box (green) and the BSR (gray). Everything else is supporting context.
Reading the BSR Line
BSR tells you how often a product sells. The lower the number, the more frequently it sells. For BNPL arbitrage, BSR velocity determines whether your inventory will sell before your payment is due.
| BSR Pattern | Rating | What It Means for BNPL Arbitrage |
|---|---|---|
| Flat under 100,000 | Excellent | Sells daily or multiple times per day. Ideal for BNPL arbitrage — guaranteed sell-through before payments are due. |
| Flat 100K–250K | Good | Sells regularly. May take 7–21 days per unit. Afterpay Pay in 4 timing works well here. |
| Flat 250K–400K | Marginal | Sells 1–4 times per month. Use Klarna Pay in 4 (longer window) if buying. Require higher ROI to compensate for timing risk. |
| Erratic spikes | Risky | Unpredictable velocity. Skip unless ROI is exceptional and you have cash buffer to cover slow periods. |
| Regularly above 500K | Avoid | Sells infrequently. Storage fees will accumulate. BNPL payments will be due before inventory clears. |
How to Spot a Price Spike
This is the skill that separates profitable arbitrage sellers from ones who constantly wonder why they're losing money. Price spikes are the #1 cause of bad buys.
- ✓Buy Box flat for 60–90 days
- ✓Current price matches 90-day average
- ✓Orange (Amazon) line present and consistent
- ✓BSR chart flat at a low number
- ✓Low number of total sellers
- ✗Sharp upward movement in last 30 days
- ✗Current price 50%+ above 90-day average
- ✗Gap in orange line (Amazon out of stock)
- ✗BSR improved suddenly (spike demand)
- ✗Third-party sellers raised prices together
The spike rule: If the current price is more than 30% above where it spent the majority of the past 90 days, treat it as a spike. Do not buy clearance inventory to sell at a spiked price unless you have documented evidence (seasonal pattern, trending product) that the higher price is the new normal.
The 30-Second Sourcing Check
In-store, you have limited time. Here's the Keepa check in order of priority:
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1Is the Buy Box flat for 90 days?Glance at the green line. If it's roughly flat at or near the current price: proceed. If there's a sharp recent spike: put it back.
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2Is the BSR flat under 250K?Look at the gray line (right axis). Flat and low = consistent sales. Spiky or high = slow or unpredictable seller.
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3Is the orange Amazon line present?If Amazon's line disappeared recently and the price jumped, you're looking at a third-party spike, not a real price.
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4How many sellers?Check the seller count trend. A sudden jump in sellers means competition just increased — which may compress the price before you sell.
SellerAmp shows the Keepa 90-day chart in a single tap per scan. No switching apps, no separate browser tab. On a busy sourcing run, this is the difference between checking Keepa on 40 products vs checking it on 5.
5 Real Chart Scenarios — Buy or Pass?
Amazon is in stock, price is real, BSR confirms fast sales. Classic green-light product.
Price is a spike caused by Amazon going out of stock. It will return to $28. You'd be selling at a loss.
BSR spikes mean erratic sales velocity. Your BNPL payment may be due before the item sells.
New seller flood may compress price. Consider: is your margin wide enough to absorb a 15% price drop?
Low competition, stable price, consistent BSR. Clean signal.
SellerAmp shows all five of these chart signals in one scan result — including the seller count trend and Keepa 90-day chart. The fastest way to run this check in-store.
Read the SellerAmp Review →Frequently Asked Questions
A Keepa chart shows the price history of an Amazon product over time. For retail arbitrage, the two most important things it tells you are: (1) whether the current Amazon price is stable or a temporary spike, and (2) whether the product sells consistently (steady BSR) or sporadically (erratic BSR). This prevents you from buying inventory on a fake price signal.
BSR stands for Best Sellers Rank — Amazon's ranking of how well a product sells relative to all other products in its category. On a Keepa chart, BSR is displayed as a gray line on the right axis. Lower BSR = sells more frequently. A flat BSR line under 200,000 means the product sells reliably. A BSR that spikes to 500,000+ regularly means it sells infrequently.
A price spike appears as a sudden sharp upward movement in the Buy Box (green) or New price line that is significantly above the price range for the preceding 60–90 days. If the current price is $45 but the Keepa chart shows it has been $22–$28 for the past 90 days, the current $45 is a spike. Do not buy clearance inventory to sell at a spiked price — it will return to the historical range before your inventory arrives at FBA.
You need a paid Keepa subscription ($19/month) to see full 90-day price history. Free Keepa only shows limited data. Alternatively, SellerAmp ($19.99/month) includes Keepa charts directly in the mobile scanner — so you see price history on every in-store scan without switching apps. Most arbitrage sellers use SellerAmp on their phone and skip the separate Keepa subscription.