OTTO Sponsored Product Ads: budget, bids and how to calculate ACoS

How do bids work for OTTO Sponsored Product Ads?

Sponsored Product Ads (SPA) place your products prominently in search results and product lists on otto.de. You book them self-service in OTTO Partner Connect. The OTTO Market API describes the bid as the maximum amount you are willing to pay per click (in cents). What a click actually costs shows up in reporting as the average cost per click (CPC): ad spend divided by clicks.

OTTO does not publish how its auction decides. So don't assume the highest bid automatically wins position 1 – relevance usually matters for ads too.

Automatic or manual campaign?

According to the API documentation there are two campaign types:

• Automatic: OTTO chooses the targeting. You can still add negative keywords to exclude irrelevant search terms.
• Manual (keyword targeting): you book specific search terms with exact, phrase or broad match and can set a separate bid per keyword.

Keyword targeting has been available since August 2025. From its beta test, OTTO reported 120% higher ROAS and a 50% higher click-through rate for keyword-based ads compared with automatic campaigns – OTTO's own figures, not a guarantee for your range. Work out which terms fit first with keyword research for OTTO.

How do you set the budget?

The API gives every campaign a budget with a period: daily, weekly, monthly or lifetime. On top of that comes pacing: spend as fast as possible, or spread evenly over the period.

• Even is usually the safe choice, so your budget isn't gone by mid-morning.
• As fast as possible can make sense when a promotion runs only briefly and you want maximum visibility.

Start with a budget you can afford to lose without sales, and only raise it once the numbers work.

ACoS and ROAS: the formulas

• ROAS (return on ad spend) = ad revenue ÷ ad spend
• ACoS (advertising cost of sale) = ad spend ÷ ad revenue × 100%
• CPC = ad spend ÷ clicks
• Click-through rate (CTR) = clicks ÷ impressions

OTTO's SPA reporting shows impressions, clicks, spend, CTR, CPC, ROAS and attributed revenue. The documentation doesn't list ACoS – you simply calculate it as the inverse: a ROAS of 5 equals an ACoS of 20%. Note that revenue is attributed at product level, so it only counts purchases that trace directly back to a click on that product's ad.

Worked example: does the campaign pay off?

The numbers below are a made-up example for illustration, not OTTO averages:

1. A campaign costs €60 in one week for 150 clicks – a CPC of €0.40.
2. The ads sell 8 products at €45 each: €360 ad revenue.
3. ROAS = 360 ÷ 60 = 6; ACoS = 60 ÷ 360 = 16.7%.
4. After purchase cost, commission, shipping and returns, assume 25% of the selling price is left – that is your break-even ACoS.
5. 16.7% is below 25%: the campaign makes money. At an ACoS of 30%, every advertised sale would lose you money.

Your margin depends heavily on fees – commission rates by category are covered in OTTO marketplace fees and commission.

What should you check regularly?

• Search term report: keyword reporting shows which search terms triggered your ads. Terms with clicks but no sales are candidates for lower bids or negative keywords.
• Bids per keyword: push strong terms with good ROAS, lower weak ones.
• Time frame: reporting goes back up to 90 days. Judge campaigns over several weeks, not after one day.
• Stock: ads for nearly sold-out products burn budget.

Look at ad position and organic position together

ACoS doesn't tell you where your ad appears – or whether your product already ranks high organically. If it is already in position 2 organically, an expensive ad often adds little extra revenue. A rank tracker such as MarktRank shows overall, organic and ad position per keyword separately, so you can see where advertising pays. More in OTTO Sponsored Product Ads: measuring ad position.

Frequently asked questions