When you advertise on bol.com, you'll soon come across the term ACoS. But what exactly is ACoS, how do you calculate it, and - perhaps even more importantly - what's a good ACoS for your products? In this article, we'll explain everything about Advertising Cost of Sale, the difference with TACoS, and provide practical tips to lower your advertising costs.
What is ACoS and why is it important?
ACoS stands for Advertising Cost of Sale and is a percentage that indicates how much you spend on advertising costs relative to the revenue you generate through those ads. It's the most important KPI for bol.com sellers who use Sponsored Products or other advertising forms on the platform.
A low ACoS means you spend relatively little to make a sale, while a high ACoS indicates that your advertising costs are eating into a large part of your revenue. By monitoring your ACoS, you can determine whether your ad campaigns are profitable and where you can optimize.
How do you calculate ACoS?
The formula for ACoS is simple:
ACoS = (Advertising costs ÷ Ad revenue) × 100%
Let's say you spend €50 on ads and generate €500 in revenue. Then your ACoS is:
(€50 ÷ €500) × 100% = 10%
This means that for every euro in revenue from ads, you spend 10 cents on advertising costs. Whether you consider this a good result depends on your profit margin - more on that later.
What's a good ACoS?
There's no universal 'good' ACoS, as it strongly depends on your product category, profit margin, and business goals. As a rule of thumb: your ACoS should be lower than your gross profit margin to advertise profitably.
| Profit margin | Maximum ACoS (break-even) | Target ACoS (profitable) | Assessment |
|---|---|---|---|
| 10% | 10% | < 7% | Very tight - optimize sharply |
| 20% | 20% | < 14% | Tight - focus on top performers |
| 30% | 30% | < 20% | Average - room for growth |
| 40% | 40% | < 28% | Comfortable - more room for experimentation |
| 50%+ | 50%+ | < 35% | Roomy - aggressive advertising possible |
Use the Boloo Profit Calculator to calculate your exact profit margin per product, so you know what your maximum ACoS can be.
ACoS vs. TACoS: what's the difference?
Besides ACoS, there's also TACoS (Total Advertising Cost of Sales). Although they're similar, they measure something entirely different:
| Feature | ACoS | TACoS |
|---|---|---|
| Full name | Advertising Cost of Sale | Total Advertising Cost of Sales |
| Formula | Advertising costs ÷ Ad revenue | Advertising costs ÷ Total revenue |
| What it measures | Efficiency of ads | Impact of ads on total revenue |
| Revenue included | Only from ads | Ads + organic |
| Best for | Short-term campaign optimization | Long-term strategic analysis |
| Typical percentage | 10%–30% | 5%–15% |
Important insight: a decreasing TACoS with a stable ACoS means that your ads are also boosting your organic sales - a sign of growing brand awareness and better organic rankings.
When to use which metric?
Use ACoS for daily adjustments of individual campaigns and keywords. Use TACoS for monthly and quarterly analyses to determine if your advertising strategy contributes to sustainable growth. The most successful sellers on bol.com combine both metrics.
Lowering Your ACoS: 7 Practical Tips
1. Optimize Your Keywords
Analyze which keywords convert and which don't. Pause keywords with a high ACoS and shift budget to the best-performing keywords. Use the Boloo Keyword Verkenner to discover new promising keywords with less competition.
2. Improve Your Product Listings
A well-optimized product page leads to a higher conversion rate, which automatically lowers your ACoS. Ensure strong titles, good bulletpoints, and professional photos. With the Boloo Listing Generator AI, you can create optimized listings in minutes.
3. Use Negative Keywords
Add keywords that generate clicks but don't lead to sales as negative keywords. This prevents unnecessary advertising costs and directly lowers your ACoS.
4. Adjust Your Bids
Lower bids for keywords with a too high ACoS and increase them for keywords that convert profitably. Start with lower bids and gradually scale up based on results.
5. Focus on Your Bestsellers
Prioritize advertising on products with a proven high conversion rate and good profit margin. These products generally generate the lowest ACoS. Check with the Boloo Sales Dashboard which products perform best.
6. Monitor Seasonal Patterns
Competition on bol.com fluctuates strongly per season. Around holidays and peak periods, bid prices rise, which can drive up your ACoS. Adjust your budgets and bids based on these patterns.
7. Test Different Ad Types
Bol.com offers multiple ad formats. Test Sponsored Products alongside other options to discover which type yields the lowest ACoS for your product category.
Common Mistakes in ACoS Optimization
Only Focusing on ACoS
A low ACoS isn't always better. If you lower your ACoS too aggressively by reducing bids, you might lose visibility and market share. A slightly higher ACoS can lead to significantly more revenue and ultimately more absolute profit.
Stopping Campaigns Too Quickly
New campaigns need time to optimize. Bol.com's algorithm needs at least 2-4 weeks of data to effectively display your ads. Give campaigns enough time before drawing conclusions about the ACoS.
Not Considering Profit Margin
An ACoS of 25% is excellent with a profit margin of 50%, but disastrous with a margin of 20%. Always calculate your profit margin per product before determining your ACoS targets.
Ignoring Organic Impact
Ads on bol.com generate extra sales that improve your organic ranking. This "flywheel effect" isn't visible in your ACoS, but it is in your TACoS. Therefore, keep an eye on both metrics.
ACoS Benchmarks per Product Category
The average ACoS varies greatly per category on bol.com. Below is an indication based on market data:
| Product category | Average ACoS | Competition level |
|---|---|---|
| Electronics & accessories | 12%–18% | High |
| Home & living | 15%–22% | Average |
| Sports & leisure | 14%–20% | Average |
| Toys & kids | 18%–28% | High (seasonal) |
| Garden & DIY | 12%–18% | Average |
| Beauty & health | 16%–24% | High |
| Books & media | 8%–14% | Low |
| Pet supplies | 10%–16% | Low-average |
Frequently asked questions about ACoS
What's a good ACoS on bol.com?
A good ACoS is below your gross profit margin. For most sellers, an ACoS between 10% and 20% is a good target, but this strongly depends on your product category and margins.
How often should I check my ACoS?
Check your ACoS at least weekly at the campaign level and daily if you're investing large budgets. Use the Boloo Sales Dashboard for real-time insights into your ad performance.
Can my ACoS be above 100%?
Yes, an ACoS above 100% means you're spending more on ads than you're generating in ad revenue. This is almost always unprofitable and requires immediate action: lower bids, pause underperforming keywords, or stop the campaign.
What's the difference between ACoS and ROAS?
ROAS (Return on Ad Spend) is the inverse of ACoS. An ACoS of 20% corresponds to a ROAS of 5x (you earn 5 times your ad spend back). The formula: ROAS = 1 ÷ ACoS, or ROAS = Ad revenue ÷ Ad spend.
Does ACoS affect my organic ranking?
Indirectly, yes. Ads generate extra sales, which increase your sales velocity. Bol.com rewards popular products with higher organic rankings. A strategic investment in ads (even with higher ACoS) can therefore strengthen your organic position in the long run.
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