Open a photo

Social media alt textAlt text that fits every app.

Write it once, see how it counts on Instagram, X, LinkedIn and the rest, and where to paste it.

0 characters

Where to paste it on Instagram

After choosing the photo and filter, open Advanced settings, then Accessibility, then Write alt text. For a post already up: ⋯ → Edit → Edit alt text on the photo.

Button names change between app versions.

Free · No sign-up · Your text stays in this tab

A writer at a desk comparing a botanical photograph with the braille display beside her keyboard.
Alt textA writer comparing a flower print with her braille display.LinkedIn 59/300Pinterest 59/500Instagram 59/1,000

The reading

Nothing typed yet. The findings appear as you write, not after a button.

No grade yet

Stops the image working1
  • Stops the image workingThe image has no text alternative at all.Either describe what the image tells the reader, or mark it decorative and ship alt="". Those are the only two correct answers, and a missing attribute is neither.Rule empty

Measured against WCAG 2.1 success criterion 1.1.1 Non-text Content (Level A), which is the criterion GIGW 3.0 inherits when it asks an Indian government site to meet WCAG 2.1 Level AA.

Checked in this tab. No photo and no alt text is sent.

The limits are each platform’s ceiling, as listed in Buffer: Adding alt text to your images (checked 31 October 2026). Counts are characters as people count them; a platform may count an emoji as two. A chip turns amber at 90% of the limit and red past it. The checker underneath grades the same sentence it would grade on a web page.

One sentence, eight ceilings

Every major platform now has an alt-text field, and they disagree about how long it may be: LinkedIn stops at 300 characters, Pinterest at 500, most at 1,000 and Bluesky at 2,000. Write the description once here and the strip shows how it fares on each. Pick a platform to see where its field is.

The grade underneath is the same one the site gives alt text on a web page: subject first, no “image of”, no file names, no keyword lists. A good social description is a good description.

What it will not do

  • It does not post to any platform or connect to your accounts.
  • It does not look at your picture — you write the description; see the alt text studio for writing with the picture open.
  • Its counts are a guide: a platform's own counter has the last word, especially for emoji.

Questions people ask

How long can alt text be on each platform?

As listed by Buffer's help pages (checked 31 October 2026): Instagram 1,000, X (Twitter) 1,000, Facebook 1,000, Threads 1,000, Mastodon 1,000, Pinterest 500, LinkedIn 300, Bluesky 2,000 characters. The strip under the field counts your text against all of them at once.

Should I use the whole limit?

No. The limit is a ceiling, not a target. A person using a screen reader hears the alt text before the post's own words, and one clear sentence — usually under 125 characters — serves them better than a paragraph. The checker below the field still notes anything past 125 characters, as it does for a web page.

Do hashtags or emoji belong in alt text?

No. Alt text describes the picture. Hashtags are read out letter by letter or as run-together words, and emoji are read as their names (“face with tears of joy”). Put them in the post, not in the description.

Is my text sent anywhere?

No. The counting and the grading are done by this page in your browser. Nothing you type leaves the tab.

Why does a platform count my text differently?

This page counts characters the way people do (one emoji is one character). Some platforms count certain emoji or accented letters as two, so if you are within a few characters of a limit, leave a little room.

Where to take this next

Photographic visual for Social Media Alt Text
In this toolSocial Media Alt Text