The Headline Fit Rule: How 180 Characters Become 68, 44 and 32 Pixel Text in the Social Preview Designer

On 11 November 2026, the team behind app.onepassapps.com, known as OnePassApps, conducted a test to uncover the secret behind how their Social Preview Designer handles headlines that exceed 180 characters. The team set the headline field to different lengths and measured the resulting sizes in the exported SVG files - 30 characters, 109 characters, and 180 characters.

At 30 characters, the headline took up two lines, with each line being 68 pixels high and consuming a total of 1,072 bytes in the SVG file. With 109 characters, the headline stretched to five lines, each 44 pixels high and accounting for 1,317 bytes. When the headline reached its maximum length of 180 characters, it was broken into seven lines, each 32 pixels high and occupying a total of 1,515 bytes in the SVG file.

It's worth noting that the text reflows and rewraps as the headline grows, ensuring that no words are clipped or abbreviated. The description, eyebrow, and footer also adjust their sizes and line breaks accordingly. The preview image, sized at 1200 by 630 pixels, includes the full headline in its alt text, providing an accessible description of the card.

The Social Preview Designer follows a simple rule: inspect all text, shorten wording or change layout if the design cannot fit it readably. This rule was stated in the live guide for the app, which also mentions that the canvas sizes are examples and not guarantees, and that the preview contains the complete headline in its alt text, ensuring an accessible description of the preview.