How to Schedule Threads Carousels (4 to 6 Slide Formula)

You can plan and schedule Threads carousels without hopping between devices. PostFast lets you build a week of posts, line them up on a calendar, and publish on time. It works in your browser on desktop and on your phone, so small edits are easy anywhere.

If you want a wider overview first, read this: How to schedule Threads posts and carousels the right way.

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Table of Contents

1. What you can schedule on Threads
2. The 4 to 6 slide formula
3. Scheduling flow in PostFast
4. Native Threads options vs PostFast
5. Cross posting to Instagram and more
6. Specs that keep carousels clean
7. FAQ
8. Copyable checklists

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What you can schedule on Threads

PostFast supports the main post types on Threads:

• Text posts
• Single image posts
• Video posts
• Carousels with multiple images or short clips in one post
• Drafts and scheduled posts you can move on the calendar any time

Tip: keep each carousel tight. Four to six slides is the sweet spot for saves and replies. If the story needs more, cap it at ten.

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The 4 to 6 slide formula

Use this when you want people to save the post, not just skim it.

Slide 1: Hook
Say what the reader gets. Short and clear.

Slide 2: Context
One line of setup or a quick before vs after.

Slide 3: Main step
Teach one thing. A simple diagram or short caption is enough.

Slide 4: Proof or example
Numbers, a mini case, or a side by side.

Slide 5: Takeaway
What to remember. One sentence is stronger than a paragraph.

Slide 6: Call to action
Invite replies or point to the next step.

Helpful formatting:

• Use the same ratio across all slides
• Large type, good spacing
• One idea per slide

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Scheduling flow in PostFast

1. Connect Threads
   Sign in and connect your Threads account once.

2. New Post → Choose Threads
   Upload slides in order. You can mix images and short clips if it helps the story. PostFast prepares files before publishing so aspect ratios and durations fit Threads rules.

3. Write the caption
   Put the hook in line one.

4. Pick date and time
   Choose posting windows that work for your audience and keep a weekly rhythm you can repeat.

5. Schedule
   Posts go out on time. Open PostFast on your phone any time to shift a slot or tweak the caption.

Want to run this at scale

• PostFast supports cross posting with different captions per platform.
• You can automate pieces of the workflow with the public API. See the API docs.

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Native Threads options vs PostFast

Threads offers simple built in tools that are fine for quick posts on your phone. PostFast is better when you plan a week at once or publish to more than one platform.

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Cross posting to Instagram and more

When a carousel works on Threads, reuse it elsewhere in minutes.

• Instagram. Choose the platform, adjust the caption if needed, and set the time. See the Instagram integration.
• TikTok. Use a photo carousel if it fits. See the TikTok integration.
• YouTube Shorts. Convert the strongest slide into a short vertical video. See the YouTube integration.

Create once, adapt lightly, publish everywhere.

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Specs that keep carousels clean

• Pick one ratio and stick with it across the set. 1:1, 4:5, or 9:16 all look good on mobile.
• Resolution. Export at 1080 on the short edge.
• Safe margins. Leave space near the edges so UI does not cover text.
• Order. Lead with the clearest slide. Do not bury the hook.

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FAQ

How many slides can I add
Up to ten is supported. Four to six is usually the best range for completion and saves.

Can I schedule from desktop and phone
Yes. PostFast runs in your browser. Same interface on both.

What is the character limit for captions
Threads allows 500 characters.

Can I mix images and videos in one carousel
Yes. Keep each slide short and easy to read on a phone.

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Copyable checklists

Carousel prep

• Choose one ratio for the whole set
• Write a one line hook for slide one
• Build slides two to five with one idea per slide
• End with one takeaway and one call to action

Posting workflow in PostFast

• Create a Carousel post for Threads
• Upload slides in order
• Add a short caption with the hook in line one
• Pick dates and times for the week
• Choose also Instagram, TikTok, or Shorts if useful
• Review on your phone and schedule

Weekly rhythm you can repeat

• Monday: draft two carousels and one text post
• Wednesday: publish the best carousel
• Thursday evening: publish the second carousel or a short video
• Friday morning: follow up with a text post or a question

If you want to try this flow, start a free trial at PostFast.