A/B Headline Tester

Enter 2+ headlines and see simulated previews in Google results, email subject lines, and social posts side-by-side.

How to Use A/B Headline Tester

1

Enter headline variants

Type two or more headline options you want to compare.
2

Review scoring criteria

Check emotional appeal, clarity, length, and power word usage scores.
3

Pick the winner

Choose the highest-scoring headline for your content or campaign.

Tested tool guide Tested browser tools Checked August 15, 2026

What A/B Headline Tester does and how it behaves

You paste in two or more headline variants and the tool renders each one as it would appear in three places: a Google search result snippet, an email client subject line, and a social post card. It estimates where each surface would cut the text off and shows the variants side by side so you can compare length and truncation at a glance. The thing people get wrong: this is not a live A/B test with real traffic or click data. Nothing is published, no impressions are measured, and there is no 'winning' headline reported - only how each version visually fits before you choose one.

How the result is produced

per-surface truncation estimate

Each surface has its own truncation behavior: Google search titles clip by rendered pixel width (not a fixed character count), email subject lines truncate based on the available rendered width, font, and screen size of the reading client rather than a client-enforced character count, and social cards clip the post text based on the platform's card layout and line-clamping, which the tool approximates with a width-based estimate rather than a single fixed cutoff. The tool applies a separate estimate for each surface to each headline you enter, so the same text can show as full-length in one preview and truncated with an ellipsis in another.

static side-by-side mockups

The previews are generated instantly from the text you type, styled to resemble the visual layout of a Google result, an inbox row, and a social post card. Nothing is sent to Google, an email service, or a social platform - it is a local rendering of typical layout conventions, not a live fetch of how that specific platform is rendering things today.

Good uses

Checking whether a blog post title and meta title will get cut off in Google search results before you publish
Previewing a newsletter subject line on a simulated mobile inbox alongside two or three alternate phrasings
Comparing several ad or social post headline options for length and truncation before scheduling any of them

Limits and checks

Truncation points are estimates based on average character widths, not the exact font metrics the live platform renders - a headline heavy in wide letters (m, w) can wrap sooner than one of the same character count using narrow letters (i, l)
This produces no click-through data, impressions, or statistical result - 'A/B' here means side-by-side visual comparison, not a measured test with a winner
Google, email clients, and social platforms periodically change preview card layout and truncation rules, and can differ between their own desktop, mobile, and app clients - the mockup reflects one common convention, not that day's exact rendering on every client

Common questions

Does this tell me which headline will get more clicks?

No. It only shows how each headline visually renders and where it truncates on each surface - it doesn't serve the headlines to real users or track engagement. To find out which one actually converts better, run a live experiment in the platform you're publishing to, such as a Google Ads experiment or your email service's A/B send feature.

Why does the same headline look a different length in the Google preview versus the email preview?

Because each surface truncates differently. Google search titles clip based on rendered pixel width, while email and social previews clip based on the rendered width and layout of the specific client or app, which varies by device. Identical text can appear complete in one preview and cut off with an ellipsis in another.

References and verification

The behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.