Short answer: Instagram Stories and Reels are 1080 × 1920 px, ratio 9:16.
Safe zones
Instagram overlays the profile name and progress bar at the top and the reply field or caption at the bottom. Keep important text out of roughly the top 250 px and the bottom 340 px. The dashed area above is the part that is always clear.
For Reels, also leave room on the right side for the like, comment and share buttons.
Same size elsewhere
1080 × 1920 is also used by Facebook Stories, TikTok, YouTube Shorts, Snapchat and WhatsApp Status — one design works on all of them.
Tips
- Headlines at 100–140 px font size; body text at least 60 px.
- Add a shadow to white text over photos.
- Design the background here and add Instagram’s interactive stickers (polls, links) in the app.