# Free Instagram Post Size Checker and Image Resizer

> Check an image's dimensions and crop, then export a square, portrait, landscape, Story, or Reel working canvas as a PNG in your browser.

- Canonical: https://fluxgravity.io/tools/instagram-post-size-checker
- Price: Free
- Category: Instagram

## What the tool does

Check a source image, preview a target crop, and download a resized PNG working canvas.

**Direct answer:** An Instagram size checker compares an image's pixel dimensions and aspect ratio with common square, portrait, landscape, Story, and Reel canvases. This tool reads the file locally and reports the closest format. It does not crop or export the image, so the final composition, safe zone, colour, compression, and mobile preview still need review.

- Local image inspection
- Aspect-ratio matching
- Crop preview and PNG export

## How to use it

### 1. Add the dimensions

Enter width and height manually or select an image for local browser inspection.

### 2. Review format matches

Compare the ratio with square, portrait, landscape, Story, and Reel conventions.

### 3. Export and review

Choose a working canvas, preview crop or fit behavior, download the PNG, then verify it in the final composer.

## Aspect ratio and resolution solve different problems

Aspect ratio describes the shape of the frame, while pixel dimensions describe its resolution. An image can have the correct 4:5 portrait ratio and still be too small for a clean export. Conversely, a large file with the wrong shape may be cropped in a way that removes important content.

This checker compares shape and reports the raw dimensions. You can also choose a target working canvas, preview either a center crop or a full-image fit, and download the resized PNG locally. Buffer documents 3:4 feed images in its own Instagram scheduling workflow, so this page includes a 3:4 canvas alongside 4:5. That documentation does not establish support for every account, publisher, or placement. Always review the exported file in your publishing composer.

## Protect the visual message before publishing

Keep essential text, product details, subtitles, and faces away from vulnerable edges. Story and Reel interfaces can cover the upper and lower areas with profile, caption, and interaction controls. A technically correct canvas can still be hard to understand if the safe area was ignored.

After confirming the format, connect the asset with an approved caption and campaign brief. FluxGravity can help produce related versions while keeping the source goal and review constraints visible.

## Common Instagram working canvases

These dimensions are useful preparation targets because they make the crop predictable. Instagram can change placements and previews, and the same asset may appear differently in feed, grid, profile, recommendations, and ads.

| Placement | Working canvas | Composition check |
| --- | --- | --- |
| Square feed post | 1080 x 1080 - 1:1 | Keep important text away from the extreme edges |
| Portrait feed post | 1080 x 1350 - 4:5 | Preview the grid and any alternate crops |
| Landscape feed post | 1080 x 566 - about 1.91:1 | Ensure small text remains readable on mobile |
| Story or Reel | 1080 x 1920 - 9:16 | Protect top and bottom UI safe areas |
| Profile image source | Large centered square | Expect a circular visible crop in many views |

Use these as preparation references, not permanent platform promises. Confirm current organic and ad specifications in the publishing interface used for the final post.

## What to check for different asset types

### Product photography

Protect the product silhouette and critical details from alternate crops. Leave enough breathing room for mobile UI and avoid adding tiny pricing text to the image.

### Carousel

Choose one aspect ratio for the sequence, align repeated elements to the same grid, and preview every slide. A strong first slide does not compensate for cropped later slides.

### Reel cover

Design for the full vertical canvas and for the smaller profile-grid presentation. Keep the subject and short label near the compositional centre.

### Text graphic

Use high contrast, a readable type size, and concise copy. Put detailed explanations in the caption rather than shrinking a paragraph into the image.

## Image preparation checklist

Correct dimensions reduce surprises, but a technically valid image can still be unreadable, misleading, or inaccessible.
- Confirm the intended placement before choosing the crop.
- Keep the source file and export a separate correctly sized version.
- Check faces, products, logos, and text in every expected crop.
- Use an appropriate colour profile and avoid repeated destructive exports.
- Preview the asset at phone size and add accurate alt text where supported.
- Verify ownership, model releases, brand permissions, and any embedded claims.

## Why correctly sized images can still fail

### Ratio mistaken for quality

An image can match 4:5 while remaining too small, over-compressed, poorly focused, or illegible on a phone.

### One crop for every surface

Feed, profile grid, recommendation previews, and ads can expose different parts of the same asset.

### UI safe zones ignored

Story and Reel controls can cover captions, faces, logos, or calls to action near the edges.

### Upscaling assumed to add detail

Changing pixel dimensions cannot recreate missing focus or authentic detail from a weak source image.

## Frequently asked questions

### Does the image leave my browser?

No. The selected image is inspected locally to read its natural width and height.

### What formats does the checker compare?

It compares square, 3:4 and 4:5 portrait, landscape, and vertical Story or Reel reference shapes.

### Does a matching ratio guarantee no crop?

No. Product interfaces and placements vary. Preview the final media in the destination composer.

### Can I check a video?

This version accepts image dimensions. Video support can be added separately.

### Does the tool edit or resize the image?

Yes. After you choose a PNG, JPEG, or WebP file, it can export a resized PNG in the browser. Crop-to-fill may remove edges; fit-entire-image adds a dark background. Check the final file before publishing.

## Continue in FluxGravity

Take the approved format, source image, message, and references into FluxGravity for connected asset production.

https://app.fluxgravity.io/agent