Tumblr has no character limit of its own, and that is the first surprise for anyone writing a limits table. A post is a list of blocks in the Neue Post Format; a text block holds 4,096 characters and a post can run to about a megabyte. What does limit a scheduled Tumblr post is elsewhere: the number of images, the video, and a set of daily caps that Tumblr does not publish as a number.
Text
| Rule | |
|---|---|
| Text block | 4,096 code points; a longer paragraph is cut at the limit and carried on |
| Whole post | About 1 MB of data; there is no stated character count |
| Hashtags | A last line made only of hashtags becomes the post's tags |
| Hashtags inside the text | Stay as text, not tags |
| Edit after publishing | Not possible through the API |
The last-line rule is how people already write for Tumblr: put the hashtags on their own final line and they become tags without the #. A link added to the post is set aside while the tags are found and put back after, so a post with a picture and a link keeps its tags.
Pictures and video
| Rule | |
|---|---|
| Pictures per post | Up to 30 |
| Picture formats | JPEG, PNG and GIF |
| Picture size | 20 MB each |
| Picture scaling | A copy at up to 2,048 pixels on the long side when a file is over the limit |
| Videos per post | One |
| Video size and length | 500 MB, up to 10 minutes |
| Alt text | Up to 4,096 characters per file |
Tumblr takes one video per post, and Preflight refuses a post with two instead of losing the second. A video is processed after upload, and Tumblr refuses a second while the first is still processing; Preflight waits ten minutes and tries again.
Daily caps and the API budget
| What it is | |
|---|---|
| Daily caps | Tumblr limits posts, pictures and videos per blog per day, and answers a 403 when one is reached |
| API calls | 1,000 an hour and 5,000 a day for each app, shared by all its users |
The daily caps are not stated as numbers in the API's answers, so a table that gives one is quoting someone else. When a cap is reached, Preflight keeps the post and tries again in about six hours, up to eight times, instead of marking it failed. Background work, such as reading figures and comments, stops well before the call budget runs out so that publishing is never the thing that is refused.
Connection
One connected account is one blog, the member's primary blog. Tumblr renews a refresh token on every use, so several accounts sharing one grant would invalidate each other; a second blog is a second connection.
After publishing
Tumblr reports notes: likes, reblogs and replies. Preflight reads those back and shows them as likes, reblogs and replies, and replies can be read from the comments inbox.
Tumblr next to the others
Thirty pictures is the most of any network here; Threads allows 20 and Instagram 10. How to connect a blog is on the Tumblr integration page, and scheduling is described on how to schedule Tumblr posts. All twelve networks are on the limits page. Tumblr is one channel on any plan, the free one included.
Figures from the Tumblr API v2 and Preflight's adapter, checked 29 October 2026.
Questions people ask
- What is the Tumblr post limit?
- Tumblr has no character limit as such. A text block holds 4,096 characters and a post can be about a megabyte. Pictures go up to 30 per post, and a post takes one video.
- How many images can I post on Tumblr?
- Up to 30 per post, as JPEG, PNG or GIF, 20 MB each.
- How long can a Tumblr video be?
- Up to 10 minutes and 500 MB, one video per post.
- Is there a daily Tumblr post limit?
- Yes, Tumblr caps posts, pictures and videos per blog per day and refuses with an error when one is reached. The API does not state the number, so Preflight waits about six hours and retries.
- How do I add tags to a scheduled Tumblr post?
- Put the hashtags on their own last line of the post. They become tags, without the hash sign. Hashtags inside the text stay as text.