What is this RSA combination counter?
A free, browser-based calculator for Google Responsive Search Ads (RSA). You add up to 15 headlines (3 of which show per impression) and up to 4 descriptions (2 show), and Google mixes and matches them into different ads. This tool tells you exactly how many distinct ads Google can assemble from your assets — and, crucially, how much that number shrinks the moment you start pinning assets to fixed positions. It counts ordered selections without repetition: P(headlines, 3) × P(descriptions, 2), then applies your pins. Everything runs locally as pure arithmetic, so nothing is uploaded.
How to use it
- Enter how many headlines and descriptions you have in the form on the left.
- For each shown slot (H1–H3, D1–D2), enter how many assets you've pinned there. Leave a slot at 0 if it's unpinned.
- Read the servable combination count on the right, along with the headline and description sub-counts and a plain-language note on how much your pinning cost you.
How pinning collapses the count
Without pinning, Google can place any headline in any of the three shown slots, so 10 headlines yield 10 × 9 × 8 = 720 orderings, and 4 descriptions yield 4 × 3 = 12 — a total of 8,640 ads. Pinning a single headline to slot H1 fixes that slot to one option and leaves only the other assets to fill H2 and H3, cutting the headline count to 1 × 9 × 8 = 72 and the total to 864 — roughly a tenfold drop. That's the trade-off: pinning guarantees a position but starves Google's optimization of variations to test.
Common use cases
- Deciding whether to pin a brand name or disclaimer, by seeing the combination cost before you commit.
- Checking you have enough headlines and descriptions to give Google room to optimize.
- Explaining to stakeholders why over-pinning hurts RSA performance.
