Your bid is the price you pay for a click. Set it too low and your ads don’t serve. Set it too high and your ACoS becomes unprofitable. Get it right and your campaigns generate consistent, scalable revenue at a margin that lets your business grow. Bidding is the most technical — and most consequential — lever in Amazon PPC.
This guide explains every bidding mechanism Amazon offers, how to calculate the right bid for any keyword, and the specific strategies that separate profitable campaigns from expensive ones.
The Three Bidding Strategies Amazon Offers
Every Sponsored Products campaign requires you to choose one of three bid strategies. This is your baseline — Amazon applies this rule to every keyword in the campaign before your keyword-level bids are considered.
1. Dynamic Bids — Down Only
Amazon lowers your bid in real time when it predicts a click is less likely to convert. Your bid never goes above your set amount, but Amazon can reduce it. This is the most cost-conservative option.
Best for: established campaigns with proven conversion data where you want to protect ACoS while maintaining volume.
2. Dynamic Bids — Up and Down
Amazon adjusts your bid both up and down based on its conversion prediction. It can increase your bid by up to 100% for top-of-search placements it considers highly likely to convert, and reduce it for lower-quality placements. This gives Amazon’s algorithm significant control.
Best for: new campaigns in the data-gathering phase, or mature campaigns where Amazon’s algorithm has enough data to make reliable predictions. Requires close ACoS monitoring.
3. Fixed Bids
Amazon never adjusts your bid. You pay exactly what you set, every time. Combined with placement multipliers (covered below), this gives you maximum manual control.
Best for: experienced PPC managers who want to control exactly what they pay per placement type, or for campaigns where Amazon’s dynamic adjustments have been consistently over-bidding.
Start new campaigns on Dynamic Down Only. It lets Amazon’s algorithm learn efficiently while protecting you from overspending before you have conversion data. Once a campaign has 30+ orders and clear keyword-level data, review and potentially switch to Fixed Bids with manual placement multipliers for tighter control.
Placement Multipliers: The Bidding Layer Most Sellers Miss
On top of your bidding strategy, Amazon lets you apply Placement Bid Adjustments — percentage multipliers that increase your effective bid for specific placements. The three placements are:
- Top of Search (first page): the premium placement at the very top of search results, rows 1–2. Highest visibility, highest CPC, often highest conversion rate.
- Rest of Search: positions further down the search results page and on subsequent pages.
- Product Pages: your ad appears on competitor (or your own) product detail pages as a related item.
You can set a multiplier of 0–900% for Top of Search and Product Pages. A 50% multiplier on Top of Search means if your keyword bid is £1.00, Amazon bids £1.50 for top-of-search placements specifically.
Why placement multipliers matter
Different placements convert at very different rates. In most categories, Top of Search converts 2–4x better than Product Pages for exact-match keywords. By setting placement multipliers, you can allocate your budget toward the placements that actually generate sales — rather than letting Amazon spread spend evenly.
| Placement | Typical CVR | Typical CPC vs base | When to increase multiplier |
|---|---|---|---|
| Top of Search | Highest (often 2–3× base) | +30–100% vs other placements | When your product has strong brand recognition or your keyword is highly specific (exact match) |
| Rest of Search | Medium | Base CPC | Rarely needs multiplier increase — it is the default baseline |
| Product Pages | Lower (shorter consideration window) | Usually lower CPC | When conquesting competitors or defending your own ASIN from competitors |
How to Calculate the Right Bid: The Target ACoS Formula
The most reliable way to set a bid is to work backwards from your target ACoS. Here’s the formula:
Example:
Selling Price = £25
Target ACoS = 30% (0.30)
Conversion Rate = 12% (0.12)
Max CPC = £25 × 0.30 × 0.12 = £0.90
This means at a £0.90 CPC, you hit exactly your 30% target ACoS. To have room to optimise downward, start at 80% of this calculated maximum — in this example, £0.72 — and increase only for keywords that prove they convert at or below your ACoS target.
What if you don’t know your conversion rate yet?
For new campaigns without data, use your listing’s organic conversion rate from Brand Analytics as your starting estimate. If you don’t have that either, use 8% as a conservative starting assumption for most product categories (adjust down to 5% for highly competitive categories, up to 15% for very niche products with strong purchase intent keywords).
Bid Optimisation: The Weekly Process
Setting bids once and leaving them is the most common PPC mistake. Amazon’s marketplace is dynamic — competitor bids change, seasonality shifts conversion rates, and as your campaign gathers data your own optimal bids change. Effective bid management means weekly review and adjustment.
Step 1: Pull your search term report
Download the Search Term Report from Campaign Manager (Reports → Advertising Reports → Search Term). This shows you actual spend, clicks, orders, and ACoS for every search term that triggered your ads over your chosen date range (use the last 30 days for optimisation cycles).
Step 2: Segment by performance
Sort your search terms into three groups:
- Winners: ACoS below target, 1+ orders. Increase bid by 10–20%.
- Borderline: ACoS slightly above target, or 10+ clicks with 0 orders. Reduce bid by 10–15% and review in 2 weeks.
- Wasters: high spend, zero orders (20+ clicks). Add as negatives immediately. Do not just reduce the bid — negative them so they stop consuming budget entirely.
Step 3: Harvest winners into manual campaigns
Any search term from your auto campaign that has generated 3+ orders should be harvested into a manual exact-match campaign with a dedicated bid. This gives you direct control over that specific term rather than relying on auto-targeting to find it again.
Never adjust a bid by more than 20% in a single week. Large sudden changes disrupt Amazon’s algorithm’s understanding of your campaign and can cause significant performance swings. Incremental adjustments — 10–15% up or down — are more sustainable and produce more predictable results over time.
Bidding for Launch vs Bidding for Profitability
The right bidding strategy is different depending on what stage your product is in:
Launch phase (0–90 days)
During launch, your primary goal is sales velocity — generating enough orders to build organic rank. Set bids 20–30% above your target ACoS calculation to ensure you win competitive positions and gather data faster. Accept a higher ACoS during this phase; it is an investment in rank, not a cost to minimise.
Growth phase (90–180 days)
Once you have organic rank on your target keywords, dial bids back toward your target ACoS. The blended TACoS (Total Advertising Cost of Sales — ad spend ÷ total revenue including organic) becomes the key metric: if TACoS is declining while revenue grows, your organic rank is building and PPC is scaling efficiently.
Mature phase (180+ days)
Maintain bids at or slightly below target ACoS on proven converters. Use the saved budget to expand into adjacent keywords and competitor ASIN targeting. At this stage, most of your volume should come from organic rank — PPC defends that rank and expands into new search territory.
Never set bids to £0.02 to “pause” a keyword. Low bids cause Amazon to deprioritise your entire campaign’s quality score. If you want to pause a keyword, pause it properly or add it as a negative. Leaving ghost bids in your campaign structure pollutes your data and signals poor campaign health to Amazon’s system.
Dayparting: When to Use Bid Scheduling
Amazon allows bid scheduling through third-party tools (Perpetua, Intentwise, Scale Insights) — you set higher bids during peak conversion hours and lower bids during off-peak hours. For most sellers, dayparting provides marginal gains at added complexity. When it is worth using:
- You have 90+ days of data and can clearly see conversion rate patterns by time of day
- Your products have strong time-of-day purchase patterns (e.g. morning coffee products, lunch food items, evening entertainment)
- You have limited budget and want to concentrate it during your highest-converting windows
Your PPC Bids Could Be Costing You Money Right Now
Most Amazon accounts we audit have bids set too high on losers and too low on winners. Our free audit shows you exactly where your budget is going and how to fix it.