Bold serif or bold sans?
Bold Serif has small strokes at the end of each letter, which looks traditional and a bit formal. Bold Sans is clean and modern, and it tends to match the default fonts used by most apps. If you are not sure, start with Bold Sans. It blends in best with the text around it.
Where bold text helps
- A headline at the top of a longer social media post.
- Section labels inside a long caption, such as the name of each step.
- A short call to action at the end of a post.
When to avoid bold Unicode text
Bold Unicode letters are different characters from normal letters. That has real side effects:
- Screen readers may read each letter as a math symbol, or skip it. Keep important information in plain text.
- Search inside apps and websites often cannot match styled letters to the normal word. Do not bold your name or keywords if you want people to find them.
- Hashtags and @mentions written in bold characters will not link correctly.
- Resumes, forms and job application systems may reject or garble these characters. Use real formatting in a document editor instead.
How the bold letters are made
Unicode includes a block called Mathematical Alphanumeric Symbols, created so mathematicians can write bold or italic variables in plain text. The generator swaps each letter for its counterpart in that block. For example, the letter A becomes U+1D400, Mathematical Bold Capital A. Digits have bold versions too, so numbers change as well.