Social media post preview

Paste a caption and pick an image to see your post as feed cards for Instagram, X, LinkedIn and Facebook: where the text folds behind more, how each network crops the image and whether the caption fits the limit. Download any card as a PNG mockup.

Instagram image ratio

Previews are approximate. Each network changes its layout by device and over time.

Your brand Instagram feed preview

Your brand

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Your brand X preview

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Your brand LinkedIn preview

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Your brand Facebook Page preview

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Runs in your browser. Your text stays on this device until you click Schedule this.

Use this tool from code

The same tool is a free API call, no account needed. It also works with our 9 SDKs and the MCP server.

curl
curl -X POST https://postboost.co/app/api/tools/social-media-post-preview -H 'Content-Type: application/json' -d '{"text":"New feature: schedule a month of posts in one sitting."}'

API docs for this tool SDK quickstart

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Why preview a post before you schedule it

Most people read a post in the feed, not on its own page. What they see there is a cut version: the first lines of the caption, a cropped image and a more link. A post that reads well in a text editor can lose its point at the fold or its headline at the crop. Seeing the feed card first lets you fix that before the post goes out.

What each card shows

Each card counts the caption against that network's limit, with the same counting rules as the character counter, and turns red when the text is too long. It cuts the text where the feed usually folds and keeps your line breaks. Instagram crops the image to the ratio you choose. X, LinkedIn and Facebook show it at its own shape within a range and crop only very tall or very wide images, from the centre.

The networks do not publish their fold positions. The folds here are approximations from published measurements, which differ by device and layout, so leave some room around them.

Write for the fold

Put the hook in the first line, before the fold, and keep the first lines short. Hashtags and links belong after it. On Instagram the name comes first in the caption line, so the first words of the caption have even less room.

Mockups for approval

Download PNG saves a card as an image you can send to a client or teammate for approval. To publish the post to every network at once, schedule it with PostBoost.

How to use

  1. Type or paste your caption. Line breaks are kept.
  2. Optionally set the display name and pick an image from your device.
  3. Choose the Instagram ratio: square, portrait or landscape.
  4. Check each card: the fold, the crop and the count against the limit.
  5. Click more to read the full text, or Download PNG to save a mockup.

FAQ

Are these previews exact?

No. Previews are approximate. Each network changes its layout by device and over time, so use the fold and the crop as a guide, not a pixel-perfect copy.

Where does Instagram cut a caption?

The feed shows about the first 125 characters or 2 lines of a caption, then more. The rest is one tap away, so put the hook first.

Where do LinkedIn and Facebook show see more?

LinkedIn folds after about 3 lines or 210 characters. Facebook shows about 480 characters before See more. Folds are approximate: published figures range from about 140 to 210 characters on LinkedIn and from about 150 to 480 on Facebook, depending on device and layout.

Why is my X card red?

The caption is over X's 280-character limit, counted the way X does: links count as 23 characters and emoji and CJK characters as 2. X Premium accounts can post longer texts.

How is my image cropped?

Instagram crops the image from the centre to the ratio you choose: 1:1, 4:5 or 1.91:1. Facebook and LinkedIn show it whole from 4:5 (portrait) to 1.91:1 (landscape) and crop taller or wider images from the centre to the nearest end of that range. X does not publish its cutoff; we use 4:5 to 2:1, the range most guides give. Keep important parts away from the edges.

Is my caption or image uploaded?

Your image never is. The preview runs in your browser: the image is read on your device and the PNG export is drawn there too. Your caption is sent to PostBoost only when you click Schedule this, which opens it as a draft in your account.

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