Alt text is a written description of an image. Screen readers read it aloud to people who cannot see the pin, and Pinterest also uses it to understand what the image shows. A good description is short, concrete and says what someone would notice first: the subject, where it is, the main colors and any text printed on the image.
This generator builds alt text from your answers, so the result describes your actual pin rather than guessing. It writes a short, a descriptive and a complete version, counts the characters against the 500 character limit and lets you copy whichever fits. Nothing you type leaves your browser.
What good alt text looks like
Describe, do not sell. "Overhead photo of three meal prep containers with rice, chicken and broccoli on a white counter" helps someone picture the pin. "Best meal prep ever, click now" does not. Keywords are fine when they are the honest name of what is shown, but stuffing a list of them makes alt text harder to listen to.
Skip "image of" for ordinary photos, because screen readers already announce an image. Do mention the type when it matters, such as an illustration, an infographic or a collage. Always include text that is printed on the image, since that is often the main message of a pin.
Alt text, titles and descriptions are different jobs
The pin title and description are written to attract clicks and match searches. Alt text is written to describe the picture. Use the title generator and description generator for those fields, and keep this one focused on what a person would see.
Check how all three fields fit their limits with the Pinterest character counter.