What are fixed bids on Amazon PPC?
Fixed bids on Amazon PPC tell Amazon to use your exact base bid for eligible auctions rather than dynamically reducing or increasing it based on the likelihood of a sale. Placement bid adjustments can still increase the effective bid for top of search, rest of search, or product pages. If a lunch box keyword has a £0.80 base bid under fixed bidding, Amazon enters eligible auctions using that £0.80 base amount rather than lowering it when a conversion appears less likely or raising it when a conversion appears more likely. The actual CPC can still be below £0.80 because the auction determines the price paid. Placement adjustments remain separate. A 50% top-of-search adjustment can raise the effective bid from £0.80 to as much as £1.20 for that placement. Fixed does not mean the same final bid in every placement when additional bidding controls are active. Fixed bids may suit campaigns where consistent auction participation matters more than allowing Amazon to reduce bids, such as selected brand defence, awareness, category visibility, or carefully monitored product targeting. They can also provide a clean control strategy when testing Amazon's dynamic bidding options. They are usually less suitable when the main goal is efficiency and auction quality varies widely. Because Amazon does not lower the base bid for opportunities it predicts are less likely to convert, fixed bidding can generate more traffic while producing a higher CPC or ACoS. Fixed bids are not automatically better or worse. They provide more consistent base bidding, while dynamic down-only can reduce exposure in auctions Amazon predicts are less likely to convert. Dynamic up-and-down can also increase bids for stronger opportunities, creating more variation and a higher maximum effective bid. Compare strategies using similar campaign structures and a meaningful data period. Assess sales, CPC, conversion rate, ACoS, placement, and total spend. Choose the strategy that supports the campaign's goal rather than the one that produces the most impressions.
Fixed bids tell Amazon to use your exact base bid for every eligible auction, subject to placement adjustments. Learn when this strategy fits.