Home » PPC Optimization: Experiments in Punctuation – optimize conversion rates of adwords text ads

PPC Optimization: Experiments in Punctuation – optimize conversion rates of adwords text ads


By varying the punctuation and plurals within your text ads, you can optimize their conversion rate and cost per conversion. This article shows a case study of call only text ad optimization.

After you’ve tried different PPC ad text position and display URL expansion it’s time to tweak punctuation! Varying punctuation on winning ads can improve conversion rates. You need to be careful, however, when varying punctuation in your text ads. Google has strict guidelines on what it will accept, with the risk of having your ads disapproved in the offing.

“Exclamation marks in the ad headline; repeated punctuation or symbols; symbols, numbers, and letters that don’t adhere to their true meaning or purpose, such as using “@ home” to mean “at home”; non-standard use of superscripts; non-standard symbols or characters, such as asterisks and vertical lines; bullet points and ellipses; excessive or gimmicky use of numbers, symbols, or punctuation, such as f1owers, fl@wers, Flowers!!!, f*l*o*w*e*r*s, F.L.O.W.E.R.S.”

There are exceptions of course like trademarks, brand names, and symbols used in commonly acceptable ways like “5*”. So essentially you can use numbers (“24 Hours,” “24/7 Service”), dashes (i.e., “eco-friendly”), commas, periods, and exclamation points!

Vary the Best Text Ads

As you test more ad text you’ll find that some text ads convert better than others. After you are sure you’ve got a winner, try different variations. You can flip words around, add expanded display URLs, tweak headlines, and vary punctuation. In this example we took the best text ad in our Ann Arbor Car Service campaign and tweaked (see Figure 1).

PPC Best Ad for Ann Arbor Car Service

Figure 1: PPC Best Text Ad Baseline

This call only ad has an 88.9% conversion rate, costing $1.10 per click. This ad has two attributes we look for, high conversion and low cost. Next we tried varying the punctuation after the final word “Service” (see Figure 2).

PPC Best Ad Punctuation & Plural Variants

Figure 2: PPC Text Ad Punctuation & Plural Variants

Results of Punctuation and Plural Variants

Adding a mere period after the last word in the ad (“Service.”) improved the conversion rate to 100% from 88.9%. It also kept the click-through rate about the same (6.9%).
The cost per click, however, increased from $1.10 to $1.61 (see Figure 2). We next tried changing the period to an exclamation point (“!”). This also improved the conversion rate to 100%, but jacked up the cost per click to $2.24, which was too high. Finally, we made the word service plural (“Services.”) and added a period. We found previously that making the word service plural lowered the cost per click in other ads. This tweak of our best ad boosted the conversion rate to 100% while lowering the cost per click (and call) to $0.83. As a bonus, it also improved the click-through rate from 6.9% to 8.8%. So far, this is the winning variant of our best ad.

Further Tweaks

Using an exclamation point and a plural is another possibility, but we think the cost per click may be too high for our criteria. We could also try varying the punctuation elsewhere in text ads, but we’ve found that the last word usually gives the most bang for the buck.


By varying the punctuation and plurals within your text ads, you can optimize their conversion rate and cost per conversion. Adding a plural plus a period to the end of our best text ad boosted the conversion rate by more than 12%, and lowered our cost per click by 24%.

Further Reading

Google Adwords: Style and Spelling
Google Adwords’ guide to style and spelling of ad text includes a section on acceptable punctuation.
This Ann Arbor and Southfield Michigan-based green taxi cab company volunteered their AdWords campaign as the subject of this article.
PPC Optimization: Ad Text Position
Leading with benefits can improve PPC text ad conversion rates. We show a case study that improves conversion rates by 1.8X.
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PPC Optimization: Average Income Targeting
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PPC Optimization: Display URL Expansion
By including keywords or calls to action in your display URLs you can boost text ad performance in Google Adwords. This article shows a real-world example of display URL optimization.
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