Per-Platform Limits and Image Specs
Each social network has its own rules for caption length, image size, video length, and what kinds of posts are allowed. PostFriendly warns you when a post breaks one of these — but knowing them up front saves time.
Caption length
| Network |
Limit |
Sweet spot |
| Facebook |
63,206 characters |
40–80 |
| Instagram |
2,200 characters |
125–150 (before "...more") |
| X (Twitter) |
280 characters |
Under 240 leaves room for engagement |
| LinkedIn |
3,000 characters |
150–300 |
| TikTok |
2,200 characters |
100–150 |
"Sweet spot" is what tends to perform — not a hard rule.
Image specs
Facebook
- Feed (square) 1080×1080
- Feed (landscape) 1200×630
- Stories 1080×1920
- Format JPG, PNG, WebP
- Max file size 30 MB
Instagram
- Feed (square) 1080×1080
- Feed (portrait) 1080×1350
- Feed (landscape) 1080×566
- Stories / Reels cover 1080×1920
- Format JPG, PNG
- Max file size 30 MB
X (Twitter)
- Single image 1600×900 (landscape) or 1080×1080 (square)
- Format JPG, PNG, WebP, GIF
- Max file size 5 MB for images, 15 MB for GIFs
LinkedIn
- Feed 1200×627 (landscape) or 1080×1080 (square)
- Format JPG, PNG, GIF
- Max file size 5 MB
TikTok
- Photo carousel 1080×1920 (portrait)
- Format JPG, PNG, WebP
- Max file size 10 MB
Video specs
| Network |
Max length |
Best format |
Max size |
| Facebook |
240 minutes |
MP4 (H.264) |
10 GB |
| Instagram Feed |
60 seconds |
MP4 (H.264) |
100 MB |
| Instagram Reels |
90 seconds |
MP4 (H.264), 9:16 |
250 MB |
| X |
2 minutes 20 seconds |
MP4 (H.264) |
512 MB |
| LinkedIn |
10 minutes |
MP4 (H.264) |
5 GB |
| TikTok |
10 minutes |
MP4 (H.264), 9:16 |
1 GB |
Carousel / multi-image
| Network |
Max items |
| Facebook |
10 |
| Instagram |
10 |
| X |
4 |
| LinkedIn |
9 |
| TikTok |
35 (photo mode) |
Hashtag count
| Network |
Allowed |
Recommended |
| Instagram |
30 |
5–15 |
| TikTok |
unlimited |
3–5 |
| X |
unlimited |
1–2 |
| LinkedIn |
unlimited |
3–5 |
| Facebook |
unlimited |
0–2 |
Mentions
@name works on Facebook, Instagram, X, and LinkedIn. PostFriendly autocompletes public accounts the network exposes. TikTok mentions work only for accounts you follow.
What PostFriendly does automatically
- Resizes images down to fit when they're too big (never upscales — quality matters).
- Warns before publishing if a post breaks a hard limit.
- Adjusts captions per-channel only when you tell it to (per-channel edit in the composer).
What you have to handle
- Cropping — we don't crop your face out of a photo to make it square. You set the crop.
- Per-channel tone — a 280-character X post and a 1,200-word LinkedIn post are different writing tasks. The AI suggester can help with both.