Amazon ACoS Explained

ACoS is perhaps the most important metric you’ll track as an Amazon seller. It measures advertising efficiency and directly determines whether your advertising is profitable or burning money. Understanding ACoS and how to optimize it is critical to scaling your Amazon business profitably.

What Is ACoS?

ACoS stands for Advertising Cost of Sale. It measures the percentage of ad revenue spent on advertising. The formula is simple:

ACoS = (Total Ad Spend ÷ Total Ad Revenue) × 100

For example:

  • You spend £100 on ads
  • Those ads generate £300 in revenue
  • Your ACoS = (£100 ÷ £300) × 100 = 33%

This means that 33 pence of every pound of ad revenue goes toward advertising costs. The remaining 67 pence goes to your gross profit (before other costs like COGS, shipping, returns).

The lower your ACoS, the more profitable your advertising. A 20% ACoS is more efficient than a 30% ACoS, which is more efficient than a 50% ACoS.

What Is a Good ACoS?

This is the question every Amazon seller asks, and the answer is: it depends on your margins. There’s no universal “good” ACoS because profitability depends on how much it costs you to make and sell your product.

Break-Even ACoS

Your break-even ACoS equals your profit margin percentage. If you make a 40% profit on each sale (after COGS, Amazon fees, shipping, returns), then a 40% ACoS means you’re breaking even on advertising. No profit, but no loss.

If your profit margin is 40% and your ACoS is 30%, you’re profitable. If your ACoS is 50%, you’re losing money on advertising.

Target ACoS

Your target ACoS should be your break-even ACoS minus your desired profit margin on advertising.

Example:

  • Product cost: £10
  • Selling price: £25
  • Amazon fees, shipping, returns: £5
  • Profit: £10 (40% margin)
  • Break-even ACoS: 40%
  • If you want 50% of your profit to come from advertising margin, your target ACoS: 20%

In this example, a 20% ACoS means you’re spending £0.20 of your £0.40 profit on advertising, keeping £0.20 as pure advertising profit. This is a reasonable balance.

Industry Average

The Amazon advertising industry average is approximately 30% ACoS. However, this average masks significant variation by category and product type. Some highly competitive categories average 35-40% ACoS. Some niche categories average 15-20%.

Don’t use the industry average as your target. Calculate your specific break-even ACoS and target based on your actual profit margins.

Understanding Profitability Through ACoS

ACoS is a profitability metric. Here’s how to think about it:

Profit Margin ACoS 20% ACoS 30% ACoS 50%
15% margin Profitable Loss Loss
30% margin Profitable Profitable Loss
50% margin Profitable Profitable Profitable

This table shows why you must know your profit margins. A 50% ACoS is acceptable for high-margin products but catastrophic for low-margin products.

ACoS vs. ROAS

ROAS stands for Return on Ad Spend. It’s calculated as:

ROAS = (Total Ad Revenue ÷ Total Ad Spend) × 100

ROAS is the inverse of ACoS. If your ACoS is 30%, your ROAS is approximately 333% or 3.33x (meaning you get £3.33 back for every £1 spent).

Some sellers prefer ROAS because it sounds better (“3.33x return” sounds more impressive than “30% ACoS”), but they measure the same thing. Use whichever metric feels more intuitive to you. Amazon Seller Central shows both.

TACoS: The Broader Profitability Picture

ACoS only measures revenue that came directly from your ads. However, your products also generate organic sales (from search results, your storefront, returning customers). TACoS (Total Advertising Cost of Sale) provides a broader perspective:

TACoS = (Total Ad Spend ÷ Total Revenue) × 100

This includes both ad-driven and organic revenue. For example:

  • Total ad spend: £100
  • Ad-driven revenue: £300 (ACoS: 33%)
  • Organic revenue: £200
  • Total revenue: £500
  • TACoS: (£100 ÷ £500) × 100 = 20%

Your TACoS is 20%, even though your ACoS is 33%. This is why TACoS matters. It shows how advertising costs affect your total business, not just ad-driven sales.

A healthy TACoS target is typically under 20%. If your TACoS exceeds 20%, your advertising is consuming a significant portion of total revenue. This is fine if you’re in a growth phase, but not sustainable long-term.

Optimizing Your ACoS

Bid Strategy

Lower your bids to decrease ACoS. However, lower bids reduce visibility, which may decrease revenue faster than it decreases costs. You need to find the balance where your ACoS and revenue are both acceptable.

Negative Keywords

Add negative keywords to prevent wasting ad spend on irrelevant searches that don’t convert. If a search term drives clicks but no sales, add it as a negative keyword. This lowers ad spend without lowering revenue.

Pause Low-Performing Keywords

Identify keywords with high cost-per-conversion and low conversion rates. Pause these keywords. Redirecting budget to high-performing keywords improves overall ACoS.

Improve Listing Conversion Rate

Your ad spend matters less if your listing doesn’t convert clicks into sales. Improving your product title, photography, and A+ Content increases conversion rate, which directly decreases ACoS. A 2% increase in conversion rate can decrease ACoS by 10-15%.

Optimize for High-Volume Keywords

Keywords with high search volume typically have lower cost-per-click than ultra-niche keywords. Bidding on “baby spoon” may be cheaper than “ergonomic curved silicone feeding spoon for infants with heat-reactive color change”. Target high-volume keywords first, then niche keywords second.

ACoS Varies by Product and Campaign

Your overall ACoS across all products may be 30%, but individual products should have different targets:

New Product Launches

New products without reviews have lower conversion rates. You should expect higher ACoS (35-50%+) during launch phase. Accept this as the cost of building reviews and visibility. As reviews accumulate, conversion rate improves and ACoS decreases naturally.

Bestsellers

Established products with many reviews have high organic visibility and conversion rates. You should target low ACoS (15-25%) for bestsellers. These products can afford lower advertising spend because they already have strong organic search visibility.

High-Margin Products

Products with 50%+ margins can support 40-50% ACoS and still be profitable. Invest aggressively in advertising for high-margin products to drive volume.

Low-Margin Products

Products with 15-20% margins require strict ACoS discipline (target 10-15% ACoS). Aggressive advertising isn’t feasible for these products.

Seasonal ACoS Variation

ACoS varies seasonally due to competition and shopping patterns. During peak shopping seasons (Black Friday, Christmas), ACoS typically increases as more sellers compete for visibility. January saw ACoS peak at 32.5% in 2026. October saw low ACoS at 28% as retail competition decreased.

Plan for seasonal variation. Increase budgets during low-ACoS periods and accept higher ACoS during peak competition periods. Don’t panic if your ACoS increases by 5-10% during peak season. It’s normal.

Connecting ACoS to Your Advertising Strategy

ACoS is the output of your Sponsored Products and Sponsored Brands campaigns. Lower your ACoS by optimizing keyword targeting, pausing underperformers, and improving listing conversion rates.

Your overall advertising strategy should balance ACoS targets with revenue and market share goals. Early-stage sellers may accept higher ACoS to build market presence. Established sellers should prioritize ACoS optimization.

Frequently Asked Questions

What is ACoS and how is it calculated?

ACoS (Advertising Cost of Sale) = (Ad Spend ÷ Ad Revenue) × 100. For example, £100 spend generating £300 revenue = 33% ACoS. It measures the percentage of ad revenue spent on advertising. Lower ACoS is more efficient.

What is a good ACoS target for my products?

There’s no universal good ACoS. It depends on your profit margin. Your break-even ACoS equals your profit margin %. Your target ACoS should be lower than your break-even point. Industry average is 30%, but tailor your target to your specific margins.

How is ACoS different from ROAS and which should I focus on?

ROAS is the inverse of ACoS (30% ACoS = ~3.33x ROAS). They measure the same thing from different angles. Use whichever metric feels more intuitive. ACoS is preferable if you think in cost terms; ROAS if you think in revenue multiplier terms.

What is TACoS and why does it matter?

TACoS (Total Advertising Cost of Sale) includes both ad-driven and organic revenue. It shows advertising cost as a percentage of total business revenue. Healthy TACoS is typically under 20%. It provides a broader view than ACoS alone.

Should my ACoS target be the same for all products and cam

Campaign Organisation

How you structure your campaigns directly impacts your ability to measure performance and optimize ACoS. Properly organized campaigns allow you to isolate performance data and scale winners while pausing losers.

Portfolios for Strategic Grouping

Portfolios are groups of campaigns organized together for strategic management. Amazon portfolios allow you to:

  • Set portfolio-level budgets: Control total spend across multiple campaigns within the portfolio, rather than managing individual campaign budgets separately
  • View portfolio-level reporting: See aggregated performance across grouped campaigns, identify which portfolio drives the best ACoS
  • Create custom dashboard views: Build dashboards showing only the portfolios and metrics you care about most
  • Compare portfolio performance: Segment by brand, product line, or market (if selling internationally) to see which business unit has the strongest advertising ROI

For example, if you sell three product categories (baby feeding, baby clothing, nursery décor), create a portfolio for each. This allows you to see whether advertising is more profitable for one category and allocate budget accordingly. If baby feeding drives 20% ACoS and clothing drives 35% ACoS, you know to increase baby feeding budget and reduce clothing investment.

Best practice: Create portfolios by product category, brand, or profit margin level. Avoid portfolios that mix high-margin and low-margin products, as they obscure true profitability.

Ad Groups for Product and Keyword Segmentation

Within campaigns, ad groups contain combinations of products and targeting. An ad group typically includes:

  • One or more specific products (ASINs) you’re advertising
  • Keywords or targeting criteria you’re bidding on
  • Negative keywords that exclude certain searches
  • Bid amounts for the keywords/targeting in this group

Ad groups serve two purposes: organizing products logically and allowing you to apply different bids to different keyword or product combinations.

Organize ad groups by:

  • Product brand: Group all products from Brand A in one ad group, Brand B in another
  • Product category: Group all “baby bottles” products together, “baby feeding” in another ad group
  • Profit margin: Group high-margin products where you can bid aggressively separately from low-margin products requiring conservative bids
  • Product lifecycle stage: New products launching might need different bid strategies than established bestsellers

Example structure: A seller with diverse baby products might create:

  • Campaign: “Brand A – Premium Feeding” with ad groups for bottles, spoons, plates
  • Campaign: “Brand B – Budget Feeding” with ad groups for bottles, spoons, plates
  • Campaign: “Automatic – Broad Discovery” with automatic targeting

This structure allows the seller to apply different bids to premium versus budget products, measure performance separately by brand, and maintain automatic discovery campaigns independently. When analyzing ACoS, the seller can see that Brand A products support 25% ACoS while Brand B supports 18%, guiding budget allocation decisions.

Campaign Optimisation Framework

Campaign optimization follows a systematic approach: diagnose problems, implement targeted fixes, and measure results. This framework prevents random changes that don’t impact performance.

Fixing Low Impressions

If your campaigns have low impressions (fewer than 100 daily), customers aren’t seeing your ads. This prevents generating clicks and conversions. Solutions:

  • Add more keywords: In manual campaigns, you’re missing search opportunities. Expand your keyword list to cover more search variations. Pull your Search Term Report to identify high-converting terms customers are already searching for, then add them as keywords
  • Use broad match: Switch some keywords from Exact to Broad match to capture more search variations. Broad match generates more impressions but requires active negative keyword management
  • Raise your bids: Low bids reduce visibility. Increase bids to improve ad placement and visibility. Higher placement = more impressions
  • Check budget depletion: If your daily budget is exhausted before the day ends, you’re capping impressions artificially. Increase your daily budget to capture more opportunity
  • In automatic campaigns: If impressions are low, check your bid adjustments. You may be bidding too low for automatic targeting types that typically require higher bids

Fixing Low Click-Through Rate (CTR)

High impressions but low clicks (low CTR) means customers are seeing your ads but not clicking them. Solutions:

  • Test headlines: Your ad copy isn’t compelling. If using Sponsored Brands, test different headlines that better communicate benefit or differentiation. Run A/B tests
  • Test call-to-action: Try different CTAs (“Shop Now” vs “Learn More”). Test may reveal what resonates with your audience
  • Test product images: In Sponsored Brands grid format or Sponsored Products, low-quality or unappealing images reduce clicks. Use higher-quality product photography
  • Remove negative keywords with impressions but low clicks: If a keyword drives many impressions but few clicks, customers are seeing your ad for that term but not interested. Add as negative keyword. This prevents wasted impressions
  • Review keyword relevance: You may be bidding on keywords not truly relevant to your product. Bid only on keywords where your product is a good fit

Fixing Low Conversion Rate

Good impressions and clicks but poor conversions means ads are bringing traffic but your listing isn’t converting them. Solutions:

  • Improve product detail page: Most important factor. Ensure your title clearly describes the product, photography is professional, and your description addresses customer pain points and product benefits. A poor listing converts at 1-2%. A strong listing converts at 5-10%. This multiplies the impact of ad spend
  • Check ad-to-landing page cohesion: Your ad and product detail page should align. If your ad emphasizes “eco-friendly” but your listing doesn’t mention sustainability, shoppers experience disconnect and bounce. Ensure messaging consistency
  • Switch to Store page: For Sponsored Brands, if product detail page conversion is weak, try directing to your Brand Store or a curated collection page. Store pages with multiple products and custom messaging sometimes convert better than single product pages
  • Add A+ Content: Enhance your listing with A+ Content (brand-only feature) that tells your story and highlights benefits with images and rich formatting. A+ Content typically increases conversion rate by 20-30%
  • Optimize for mobile: Ensure your listing loads quickly on mobile and is easy to read on small screens. Most Amazon traffic is mobile

Systematic Optimization Cycle

For each campaign, follow this weekly process:

  1. Pull the Campaign Report: Identify campaigns with low impressions, low CTR, or high ACoS
  2. Diagnose the problem: Is it low impressions, low CTR, or low conversions? Or a combination?
  3. Implement targeted fix: Apply one or two specific changes addressing the identified problem
  4. Wait 7-14 days: Give changes time to generate new data. Amazon needs time to assess impact
  5. Measure results: Did the change improve performance? Repeat the cycle

Don’t make multiple changes simultaneously. This prevents understanding which change improved (or worsened) performance. Change one variable at a time and measure impact.

Keyword Optimization Cycle

Continuous keyword optimization is the backbone of successful Amazon advertising. The best campaigns improve performance week after week through systematic keyword refinement.

Step 1: Identify High-ACoS Keywords to Remove

Pull your Targeting Report and identify keywords with high ACoS that aren’t driving acceptable ROI. These are typically keywords with significant spend but poor conversion rates.

Criteria for removal: Keywords with 20+ clicks and zero conversions, or keywords with ACoS exceeding your target by 100%+ (if target is 25%, remove keywords above 50% ACoS).

Pause these keywords rather than deleting them. Pausing allows you to resume if you change your mind, while deletion is permanent.

Step 2: Add Negative Keywords for High-Spend/Low-Sales Terms

Pull your Search Term Report and identify the search queries that generated clicks but zero sales. These are customers searching for something your product doesn’t solve.

Example: You sell premium silicone baby spoons. Your Search Term Report shows clicks from “metal baby spoon” and “cheap baby spoon” searches with zero conversions. Add “metal” and “cheap” as negative keywords to prevent wasting budget on irrelevant searches.

Adding negatives is one of the highest-ROI optimizations. It directly reduces wasted spend without sacrificing good traffic.

Step 3: Promote High-Performing Auto Campaign Terms to Manual Campaigns

Automatic campaigns generate data about which searches convert well for your product. These are your most valuable keywords.

Pull your automatic campaign’s Search Term Report. Identify search terms that drove conversions and had acceptable ACoS (meeting or beating your target). Create a new manual campaign with these proven keywords, often with higher bids since you know they convert.

Example: Your automatic campaign shows these terms converted well:

  • “soft baby toy” – 5 conversions, 20% ACoS
  • “plush baby toy” – 4 conversions, 18% ACoS
  • “organic baby toy” – 3 conversions, 22% ACoS

Create a new manual campaign “High-Performing Manual” and add these as exact-match keywords with bids 10-20% higher than your automatic campaign. Since you know these keywords convert, higher bids capture more of this high-value traffic.

The Virtuous Cycle

This optimization cycle creates compounding improvements:

  1. Week 1: Run automatic and manual campaigns, gather data
  2. Week 2: Remove high-ACoS manual keywords, add negative keywords from Search Term Report
  3. Week 3: Promote best-performing auto campaign terms to new manual campaign with optimized bids
  4. Week 4: Review new manual campaign performance, identify winners to scale
  5. Repeat: Each cycle, you’re removing losers, refining the keyword mix, and scaling winners

Over 8-12 weeks, this systematic approach typically improves ACoS by 15-30% without reducing sales volume, as you’re removing waste while scaling winners.

Managing Keyword Portfolio

As your manual campaigns grow, manage your keyword portfolio systematically:

  • Monthly audit: Pull all keywords and categorize by performance (winners, neutral performers, losers)
  • Scale winners: Increase bids and daily budgets for keywords with ACoS below target
  • Optimize middle performers: Test bid increases, negative keyword additions, or placement bid adjustments
  • Pause losers: Archive keywords that consistently underperform despite optimization attempts

Over time, your portfolio shifts toward high-performing keywords and away from underperformers. This portfolio evolution is how mature campaigns achieve and sustain strong ACoS performance.

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