Free Image Resizer & Padding Calculator

Q: How do I fit an image into a square without cropping it?

Scale the image down until its longer side matches the square, then pad the shorter side. Example: a 1920×1080 image into a 1080×1080 canvas scales by 1080 ÷ 1920 = 56.25%, giving 1080×608, and the remaining 1080 − 608 = 472 px of height becomes padding — 236 px top and 236 px bottom when centered. Nothing is cropped and nothing is stretched; the empty space is the price of keeping the whole image.

Q: What is the difference between padding and cropping?

Padding adds canvas around the image — every original pixel stays visible. Cropping removes pixels from the edges to force a shape. If a platform demands an exact size and you cannot lose any of the image, pad; if the edges are expendable and the frame must be full, crop. This calculator only does the padding side; it never deletes pixels.

Last updated: October 21, 2026

Quick answer: You have an image at one size and a canvas at another — a square Instagram post, a 16:9 thumbnail, a 512×512 dataset input — and stretching it would ruin it. This free image resizer and padding calculator solves the geometry before you touch an editor. Enter your image's width and height and it gives you the simplified aspect ratio, then three answers: how to fit it inside any target canvas without cropping (scaled size plus the exact padding on each side), how to add padding to reach a bigger canvas, and how to scale it by percent or to a new width without distortion. A live preview draws the canvas and the image to scale, and you can copy the numbers or the CSS. No image upload, no signup — pure dimension math, in your browser.

Original width (px)

Original height (px)

1. Fit inside a target canvas (no cropping)

Canvas width (px)

Canvas height (px)

Placement

Allow upscaling

2. Add padding around the image

Top (px)

Right (px)

Bottom (px)

Left (px)

3. Scale (aspect ratio locked)

Scale (%)

Or: new width (px)

Padding here means empty canvas around the image — it does not crop, stretch, or cover any original pixel. Fit mode never distorts: the image is scaled by one factor for both sides, so its shape is preserved exactly.

✓ Free forever · ✓ No signup · ✓ Tool inputs stay in your browser — never sent to our servers.

How to Use the Image Resizer & Padding Calculator

Enter your image's original width and height in pixels. The simplified aspect ratio (for example 16:9), decimal ratio, orientation, and megapixel count appear immediately.
For fit-to-canvas: enter the target canvas width and height, pick a placement, and decide whether upscaling is allowed. Read the scaled image size and the exact padding on each side — those four numbers are what you set in your editor or CSS.
For add padding: enter the pixels to add on each side. The new canvas size is original plus padding on both axes — the image itself is untouched.
For scale: enter a percent (50% halves both sides) or a new width; the matching height follows from the locked aspect ratio. Nothing here stretches one side alone.
Use the preview to sanity-check the shape: the outer dashed box is the canvas, the blue box is your image at the fit size and placement. Copy the summary or the CSS snippet into your project.

Why Use Our Image Resizer & Padding Calculator?

Three calculators in one page — fit-to-canvas with padding, add-padding canvas expansion, and aspect-locked scaling, all from the same two numbers.
Per-side padding, not just a total — top, right, bottom, and left separately, so asymmetric padding and 9-position placement are exact, not guessed.
Placement control — center, corners, and edge positions redistribute the padding instead of forcing everything to the middle.
Upscale guard — fit mode caps at the original size by default, so you never accidentally invent pixels; turn it on deliberately when you mean to upscale.
Live to-scale preview — the canvas and image are drawn proportionally, so a wrong number is visible before it reaches your design.
Copyable CSS and summary — padding values and the fit result as plain text or CSS, ready for an editor, a stylesheet, or a dataset-prep script. No upload, no account.

Common Use Cases

Social media posts: A 1920×1080 photo for a 1080×1080 feed post, a 1080×1920 story, or a 1200×630 link card: get the scaled size and padding per side in seconds instead of trial-and-error in the editor.
Sellers and product photos: Marketplaces often want square images. Pad a landscape product shot to square with white padding rather than cropping the product's edges — the listing keeps the whole product visible.
Dataset and ML prep: Image models that expect a fixed input (for example 512×512 or 224×224) need every image padded to that canvas without distortion. This calculator gives the exact scale and padding per image size, which is the spec your preprocessing script needs.
Video thumbnails and slides: A 4:3 slide or screenshot into a 16:9 deck: compute the pillarbox padding so the slide sits centered with a deliberate background, not a stretched mess.
Print and framing: A photo that must fit a frame ratio (5:4, 4:3, 3:2) without cropping anyone out: the padding numbers are the mat/border sizes to cut or set in the print layout.

Image Resizer & Padding Calculator vs Alternatives

Upload-based padding tools (restorebunny, unikit, simplepic, and similar): Convenient when you want the finished file: upload, set padding, download. The cost is the upload itself (privacy, wait time, one image at a time) and most of them center everything with no per-side control. This page answers the numbers question for any size instantly, with placement control — use it to plan, then apply the numbers in any editor, or use an upload tool for the final export.
Resizing in Photoshop, GIMP, or Canva: The full-power option — canvas size dialogs do exactly this math, plus the export. The cost is opening a heavy app for a 10-second calculation and remembering which dialog holds the padding. This calculator is the fast scratchpad: get the numbers here, then set them once in the app.
CSS object-fit: contain: The browser's own fit mode: an image inside a fixed box with object-fit: contain is scaled and letterboxed automatically. It hides the numbers — you cannot read the padding off it, and it does not help when you need the dimensions for a dataset, a print file, or an editor. The calculator gives you the numbers that contain is computing silently.
CalculatorSoup's image resize calculator: A solid general resizer: new dimensions by width, height, percent, or maximum side, aspect-locked. It does not do fit-to-canvas padding or placement — the padding half of this page (scaled size plus all four padding values, with a visual preview) is the piece it skips.

Bottom line: if you need the finished padded file for one photo, an upload tool or your editor does it. If you need the exact numbers — scaled size and all four padding values, for any image size, with placement control and no upload — this page is the fast, private way to get them.

Frequently Asked Questions

How do I fit an image into a square without cropping it?

Scale the image down until its longer side matches the square, then pad the shorter side. Example: a 1920×1080 image into a 1080×1080 canvas scales by 1080 ÷ 1920 = 56.25%, giving 1080×608, and the remaining 1080 − 608 = 472 px of height becomes padding — 236 px top and 236 px bottom when centered. Nothing is cropped and nothing is stretched; the empty space is the price of keeping the whole image.

What is the difference between padding and cropping?

Padding adds canvas around the image — every original pixel stays visible. Cropping removes pixels from the edges to force a shape. If a platform demands an exact size and you cannot lose any of the image, pad; if the edges are expendable and the frame must be full, crop. This calculator only does the padding side; it never deletes pixels.

How is padding calculated?

New width = original width + left padding + right padding, and new height = original height + top padding + bottom padding. For fit mode, the scale factor is the smaller of (canvas width ÷ image width) and (canvas height ÷ image height); scaled size = original × factor (rounded to whole pixels); padding on each axis = canvas − scaled size, split by your placement choice.

Why does my image get letterbox bars on a 16:9 video?

Because its aspect ratio does not match the frame. A 4:3 photo in a 16:9 video leaves empty space on the sides (pillarboxing); a 16:9 video in a 1:1 post leaves bars top and bottom (letterboxing). Those bars are padding. This calculator tells you exactly how many pixels of bar each side needs, so you can fill them with a color, a blur, or a background instead of guessing.

Should I upscale a small image to fit a big canvas?

Usually no — upscaling invents pixels, so the result softens. Fit mode here caps at the original size by default: a 800×600 image into a 1920×1080 canvas stays 800×600 with the rest as padding, which is the honest result. Only allow upscaling when the destination genuinely requires the full canvas and you accept the quality loss (or you are upscaling with a dedicated AI upscaler, which is a different job).

Does padding change the file size or quality?

Padding changes the canvas size, not the original pixels: the image content is copied exactly, so there is no quality loss from padding itself. File size can grow slightly because the canvas is bigger (more pixels to store), especially with a solid-color fill; transparent padding in PNG adds the same pixels but compresses well when the area is uniform.