Exact match is not the cheap one: what the same keyword cost in broad and in exact

A common rule in Amazon advertising says exact match is the efficient one: you pay only for the search you chose, so the ACOS should be lower. On the accounts we measured, it mostly went the other way.

First, the three match types of a Sponsored Products keyword:

  • Exact: your ad shows for that search and its close variants (plural, small misspelling).
  • Phrase: your ad shows for searches that contain the phrase, with words before or after it.
  • Broad: your ad shows for searches that contain the words in any order, and for related searches.

The measured numbers below come from real accounts: 12 advertiser accounts in Europe and the US, 363 ad groups, Sponsored Products keyword report from March 28 to September 29, 2026. We left out the last 7 days because ad-attributed sales are not final yet. We compared ratios only inside one account and currency, never summed euros with dollars.

Exact took the most money and had the higher ACOS

In the euro accounts exact keywords took 61.2% of keyword spend, broad 30.5% and phrase 8.3%. Exact sold at 47.2% ACOS, broad at 30.3%, phrase at 46.9%.

A total like this can mislead, because one large account can carry it. So we compared inside each account. There were 11 account and currency pairs where both broad and exact had at least 50 clicks. In 9 of them broad had the lower ACOS (in 2 of these 9, exact had no sale at all, and in one the gap was only 31.6% against 32.0%). In 2 exact had the lower ACOS.

The same keyword: a higher bid, not more buyers

The cleaner test is the same keyword text in the same account, running both in broad and in exact. We found 188 such pairs. 16 of them had at least 20 clicks on both sides.

  • In 14 of the 16, the exact bid was higher.
  • In 13 of the 16, exact paid more per click.
  • In 8 of the 16, exact converted clicks to orders at a higher rate. In the other 8, broad did. That is no advantage either way.

Where both sides had at least 2 purchases (6 pairs, 3 accounts), broad had the lower ACOS in all 6.

An example from the data: a foot cream keyword in German (bids are averages over the period). In broad the bid was 0.69 euros, a click cost 0.88 euros, and 36 clicks brought 5 orders at 18.5% ACOS. In exact the bid was 1.05 euros, a click cost 1.20 euros, and 53 clicks brought 5 orders at 52.4% ACOS.

So the exact clicks were more expensive mainly because more was bid on them. Exact did not bring better buyers in exchange.

But exact is not useless

In 5 of the 16 pairs exact sold and broad did not. One example: a concrete fiber keyword in French. Broad got 39 clicks without a sale, exact sold 15 times at 16.7% ACOS. In 2 pairs it was the reverse. So the answer is not "switch everything to broad". Decide keyword by keyword.

Why the broad number is not the same search

A broad keyword collects clicks from many different searches, and its ACOS is the average of all of them. One ad group in the data held five broad keywords, among them "fußbad" (foot bath). Its 157 clicks came from 89 different searches. The search "fußbad" itself brought 26 of the clicks and none of the 5 orders.

So when the keyword report shows broad and exact side by side, it compares a mix of searches with one search and its close variants. For a single search, open the search term report.

What we could not see

We see the bid on each keyword, but not why it was set that way. We did not test what happens to sales if you lower an exact bid. And the purchases in the report are counted for 7 days after the click.

Thirty minutes for your keywords

  1. Open the Sponsored Products keyword report for the last 60 days, ending 7 days ago.
  2. Find the keywords you run both in broad and in exact. Look at those with at least 20 clicks on both sides.
  3. Compare cost per click first, then conversion rate (orders divided by clicks). If exact pays more per click but does not convert better, you pay extra for the same buyer.
  4. Set the exact bid from numbers: the most you can pay per click is the price times the conversion rate times your target ACOS. A worked example: at 20 euros, a 10% conversion rate and a 30% target ACOS, that is 0.60 euros.
  5. Before you judge the broad keyword, open the search term report of its ad group. Move the searches with at least 2 sales into exact, and judge the rest by money.

Exact gives you control over which search you pay for. It does not give you a cheaper buyer. The price of an exact click follows the bid you set on it.