What Is Amazon ACoS (and How to Calculate It)

ACoS stands for Advertising Cost of Sales. It's the single most important metric in your Amazon PPC dashboard — the number that tells you whether your advertising is making money or losing it. Understanding ACoS, what influences it, and how to optimize it is foundational to profitable Amazon selling.

This guide covers everything: the formula, how to calculate your break-even point, what targets to set for different product stages, how ACoS relates to TACoS, and practical strategies for reducing ACoS without sacrificing growth.

The ACoS Formula

ACoS is expressed as a percentage. Lower ACoS means more efficient advertising — you're spending less to generate each dollar of ad revenue. Higher ACoS means less efficient advertising. But "lower is better" isn't always true — there are strategic reasons to accept higher ACoS in certain situations, which we'll cover below.

Amazon calculates ACoS at every level: portfolio, campaign, ad group, keyword, and individual search term. This granularity is powerful — you can identify exactly which keywords are profitable and which are wasting money. The challenge is that most sellers only look at the portfolio-level ACoS and miss the per-keyword insights that drive real optimization.

What's a Good ACoS?

There's no universal "good" ACoS — it depends entirely on your profit margins. A 25% ACoS is great if your pre-PPC margin is 40% (you keep 15% profit after ad costs). The same 25% ACoS is terrible if your margin is only 20% (you're losing 5% on every ad-driven sale).

Industry benchmarks for reference: most mature Amazon sellers target 18-25% ACoS across their portfolio. High-margin products (supplements, beauty, accessories) can sustain 25-35% ACoS profitably. Low-margin products (commodity items, high-competition categories) need to stay below 15-18% ACoS to remain viable. New product launches typically run 40-60% ACoS in the first 4-8 weeks.

The key insight: your ACoS target should be derived from your specific margins, not from category averages. Two sellers in the same category with different COGS will have different break-even ACoS points. The seller with lower COGS can sustain higher ACoS and still be more profitable.

How to Calculate Your Break-Even ACoS

Your break-even ACoS is the ACoS at which your advertising generates exactly $0 profit — every dollar of ad revenue covers costs but nothing is left over. Any ACoS below this number is profitable. Any ACoS above it is losing money.

Most sellers set their target ACoS 10-15 percentage points below break-even. If your break-even is 43%, targeting 25-30% ACoS ensures each ad-driven sale generates real profit (13-18% of revenue). For help calculating your full margin stack, see our profit margin calculator guide.

ACoS Targets by Product Stage

Your ACoS target should change as your product matures through its lifecycle:

Launch phase (0-8 weeks): Accept ACoS of 40-60%. You're investing in visibility, initial sales velocity, and organic ranking. Every ad sale in this phase serves a dual purpose — generating revenue and building the sales history that improves organic ranking. High ACoS during launch is an investment, not a problem. For launch-specific guidance, see our first 90 days guide.

Growth phase (2-6 months): Target ACoS of 25-35%. Organic sales should be increasing as your ranking and reviews build. Your TACoS should be declining even if your ACoS stays flat — because organic revenue is growing alongside paid revenue. Focus on keyword graduation and negative keyword optimization to improve efficiency.

Maturity phase (6+ months): Target ACoS of 18-25%. At this stage, organic sales should represent 40-60% of total revenue. PPC shifts from a growth driver to a maintenance tool — defending ranking positions and capturing incremental customers. ACoS at this stage should be comfortably below break-even.

Harvest phase (established products): Some sellers aim for ACoS below 15% on their most established products. At this point, organic sales dominate and PPC provides incremental volume at high efficiency. Be cautious about over-optimizing here — reducing PPC too aggressively can let competitors take your organic position.

ACoS vs TACoS

ACoS measures efficiency within your advertising — ad spend relative to ad-attributed revenue. But it misses the bigger picture. TACoS (Total Advertising Cost of Sales) measures ad spend relative to ALL revenue (organic + paid). TACoS is a better measure of your overall advertising strategy's health.

Why TACoS matters more than ACoS long-term: a flat ACoS with declining TACoS means your organic sales are growing — your advertising is building sustainable ranking that generates free traffic. A flat ACoS with rising TACoS means you're becoming more dependent on paid traffic — your organic position is weakening. For a deep dive into TACoS strategy, see our TACoS explainer.

Healthy TACoS benchmarks: 8-12% for established products, 12-18% for growth-phase products, and 20-30% for launch-phase products. If your TACoS exceeds 30% long-term, your product may be too dependent on advertising to be sustainably profitable.

Where to Find Your ACoS

In Seller Central, navigate to Advertising → Campaign Manager. ACoS is displayed at every level: portfolio (top-level overview), campaign (click any campaign), ad group (within each campaign), keyword (within each ad group), and search term (via the Search Term Report). For the most actionable insights, look at keyword-level ACoS — this tells you exactly which keywords are profitable and which need optimization. Our Search Term Report guide covers how to extract maximum value from per-keyword data.

How to Reduce Your ACoS

ACoS has two components: spend and revenue. You can reduce ACoS by reducing spend (negating wasteful keywords, lowering bids on underperformers) or by increasing revenue per click (improving your listing's conversion rate).

Quick wins (reduce spend): Negate search terms with 20+ clicks and zero conversions — this eliminates pure waste. Reduce bids on keywords with ACoS above 2x your target — they're likely overpaying for position. Pause keywords that have spent more than 2x your product price with zero conversions — they've had enough data to prove they won't convert.

Strategic improvements (increase revenue per click): Improve your listing's conversion rate — every improvement in conversion rate directly reduces ACoS because each click is more likely to generate revenue. Focus on main image quality, price competitiveness, review count, and bullet point clarity. A/B test your main image if you have Brand Registry — a 2% conversion rate improvement can reduce ACoS by 10-15%.

Structural optimization: Graduate proven winners from auto/broad campaigns to manual exact match where they get optimized bids. Separate campaigns by match type to allocate budget efficiently between discovery (auto/broad) and extraction (exact). Set dayparting adjustments if your data shows certain hours convert better than others. For a complete ACoS reduction strategy, see our lower ACoS guide.

Common ACoS Mistakes

Optimizing ACoS without considering TACoS. Aggressively cutting PPC spend reduces ACoS but may also reduce organic ranking. If your organic sales drop proportionally, your TACoS stays the same or worsens — you've cut growth without improving profitability.

Setting the same target for all keywords. Not all keywords serve the same purpose. Brand defense keywords (your own brand name) should have very low ACoS (5-10%). Category keywords aim for your standard target. Competitor conquest keywords may justify higher ACoS for new customer acquisition. Set targets by keyword intent, not one-size-fits-all.

Chasing ACoS during launch. New products need aggressive PPC investment. Cutting spend because month-one ACoS is 50% will kill your launch momentum. Accept launch-phase ACoS and evaluate at 90 days, not 30.

Ignoring conversion rate. Most sellers try to reduce ACoS by adjusting bids and negating keywords — both spend-side tactics. But the conversion rate side of the equation is often higher-impact. A listing that converts at 15% instead of 10% effectively reduces ACoS by 33% without changing a single bid.

What This Looks Like in Practice

Here's how an AI agent presents your ACoS data with context and actionable recommendations — not just numbers, but what to do about them: