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What is ACOS, ROAS, and TACOS? How to interpret each metric

Maria

Client Success Manager at Amersify

Introduction

Ask any Amazon advertiser what success looks like, and you’ll hear three acronyms on repeat — ACOS, ROAS, and TACOS.

They’re often misunderstood, misused, and sometimes even misleading. But when interpreted correctly, these three metrics reveal the true health of your advertising performance — not just how much you’re spending, but how efficiently you’re growing.

This guide explains what each metric means, how to calculate them, and how to use them strategically to drive profitable long-term growth.

1. What Is ACOS (Advertising Cost of Sales)?

Formula:

ACOS = (Ad Spend ÷ Ad Revenue) × 100

Example:

If you spend £100 and generate £500 in attributed sales, your ACOS is 20%.

What It Means:

ACOS measures how efficiently your ad spend converts into direct revenue. A lower ACOS means your ads are performing efficiently — but that doesn’t always mean you’re maximising growth.

Good vs Bad:

There’s no universal “good” ACOS. It depends on:

Product margin
Stage of the product lifecycle
Advertising objective (growth vs profitability)

Tip:

For new products, a higher ACOS can be acceptable while you drive rank and visibility. Focus on the long-term sales trajectory, not just short-term efficiency.

2. What Is ROAS (Return on Ad Spend)?

Formula:

ROAS = (Ad Revenue ÷ Ad Spend)

Example:

Spend £100, generate £500 — your ROAS is 5.0 (a 5x return).

What It Means:

ROAS is the inverse of ACOS, expressed as a ratio instead of a percentage. Many advertisers prefer it because it communicates return more intuitively.

Metric	High Number = Good	Low Number = Bad
ACOS	No	Yes
ROAS	Yes	No

Tip:

Amazon reports both ROAS and ACOS side by side in the Ads Console. Since 2025, the platform also reports ROAS at ad group level, helping advertisers pinpoint performance contributions more clearly. Always align your reporting language with your client or stakeholder’s preference to keep communication consistent.

3. What Is TACOS (Total Advertising Cost of Sales)?

Formula:

TACOS = (Ad Spend ÷ Total Revenue) × 100

Example:

Spend £100, generate £500 in ad-attributed sales and £500 in organic sales → total revenue = £1,000 → TACOS = 10%.

What It Means:

TACOS measures how ad spend impacts your entire account performance, not just attributed revenue. It’s the best indicator of whether your advertising investment is contributing to sustainable total sales growth. A falling TACOS indicates your advertising is improving organic sales — a hallmark of account health.

Metric	Focus	Measures
ACOS	Ad performance	Ad-attributed sales
ROAS	Ad return	Efficiency of spend
TACOS	Account health	Total business growth

Tip:

A good TACOS target depends on category, but healthy accounts generally fall between 7–12%.

4. How They Work Together

Think of it like this:

ACOS shows how efficiently your ads perform.
ROAS shows how much return you’re generating per pound spent.
TACOS shows whether your advertising is scaling your brand as a whole.

Interpretation Guide:

Scenario	ACOS	TACOS	Interpretation
ACOS ↓, TACOS ↓	Yes	Yes	Efficient and scaling organically — ideal.
ACOS ↓, TACOS ↑	Yes	No	Ads efficient, but not driving total growth — overly cautious strategy.
ACOS ↑, TACOS ↓	No	Yes	Ads more expensive short-term, but stimulating organic growth — healthy trend.
ACOS ↑, TACOS ↑	No	No	Overspending or poor optimisation — review account structure or creative.

5. How to Use These Metrics Strategically

Use ACOS to guide campaign-level bid and keyword optimisation.

Use ROAS when communicating results to management or brand stakeholders.

Use TACOS for assessing long-term profitability and growth trajectory.

Tip:

Optimise these metrics together — never in isolation. A campaign with a 25% ACOS may appear costly, but if it’s lowering TACOS by driving sustained organic rank improvements, it’s genuinely profitable.

2025 Note:

In 2025, Amazon Marketing Stream enables more precise analysis of hourly spend and sales data. You can use these real-time insights to capture performance shifts and optimise bids proactively, directly influencing TACOS improvements.

6. How to Improve These Metrics

Metric	Optimisation Focus
ACOS	Improve CTR and CVR, refine targeting, optimise bids
ROAS	Increase conversion rate, focus on high-value keywords
TACOS	Build organic rank, optimise listings, invest in long-term brand defence

Advanced Strategy:

Amazon’s Total ROAS (TROAS) metric now allows advertisers using AMC data to evaluate total return across DSP and Sponsored Ads combined. Use TROAS to understand how cross-channel exposure contributes to final purchases beyond the click level.

7. Common Mistakes

Avoid treating ACOS as your profit margin — it isn’t.

Avoid pausing high-ACOS campaigns too quickly — they often contribute to long-term rank growth.

Avoid ignoring TACOS — it’s the clearest indicator of sustainable performance gains.

FAQs

Is a low ACOS always good?

Not necessarily. It can mean you’re underspending and limiting visibility in growth phases.

What’s a healthy ROAS?

Anything above 3.0 is often strong, but brand positioning and margin affect the benchmark. Premium or niche products can perform successfully at lower ROAS levels.

How often should I review TACOS?

Weekly for active accounts, monthly for stable portfolios. Reviewing alongside Amazon Marketing Stream data can highlight hourly inefficiencies or opportunities.

Can I track TACOS in Amazon Ads?

Not directly. You’ll need to calculate it manually from Business Reports or integrate advertising and sales data using analytics tools.

Summary

ACOS, ROAS, and TACOS together reveal the true story of your account profitability.

Used strategically, they show where your revenue is coming from, whether your spend is efficient, and how well your advertising supports sustainable brand growth.

In 2025, deep data tools like Amazon Marketing Stream and TROAS make these metrics even more powerful for decision-making.

At Amersify, we use these KPIs to balance efficiency, visibility, and profitability — because successful advertising isn’t about chasing low ACOS, it’s about building long-term commercial growth.