PPM to ICO Converter

Convert PPM to ICO Online

Turn a Netpbm PPM bitmap into a Windows .ico icon for an app, desktop shortcut, or website favicon. The converter decodes your uncompressed PPM and re-saves it in the ICO container, scaling it down to one of the icon sizes Windows and browsers expect. Files upload over an encrypted connection, are processed on our servers, and are deleted automatically after a few hours — no sign-up, no watermark.

How to Convert PPM to ICO

1. Upload Your PPM File: Drag and drop your .ppm file onto the page or click "+ Add Files." You can queue several at once and convert them with the same settings.
2. Pick an Icon Resolution: Open Advanced Options and set the Image resolution Preset — the ICO list runs 256P, 192P, 180P, 128P, 64P, 48P, 32P, 24P and 16P, and 256P is what applies if you change nothing. 256, 48, 32 and 16 px are the common targets.
3. Check the Shape Before Converting (Optional): The preset is the only control an ICO target exposes — there is no quality preset, colour palette, bit-depth setting, percentage, "Keep original" or Width × Height box. It sets the icon's height, and the width follows your PPM's aspect ratio with nothing cropped or padded, so a 4:3 pixmap at 256P comes out 341×256 rather than square.
4. Convert and Download: Click "Convert" and download your .ico. No sign-up, no watermark.

PPM vs ICO at a Glance

What Each Preset Actually Produces

The preset is a height, not a bounding box. Nothing is cropped, padded or letterboxed, so the shape of your pixmap carries straight through to the icon. That matters because an ICO directory entry stores each image's width and height in a single byte apiece, with the value 0 standing in for 256 — a width above 256 simply cannot be recorded correctly.

If your PPM is not already square, crop it to 1:1 before uploading — that is the only way to get a true 256×256 icon out of a wide source. Otherwise treat 128P as the practical maximum.

Frequently Asked Questions

Why does my ICO icon look fully opaque with no transparency?

PPM has no alpha channel — it only stores red, green, and blue values per pixel — so there is nothing transparent to carry over. The resulting icon is fully opaque, with a solid background instead of a cut-out shape. If you need a transparent icon, start from a format that has alpha, such as PNG, and use our PNG to ICO converter instead.

What icon size should I choose for a favicon?

A browser favicon typically needs 16×16, 32×32, and 48×48 pixels; 16 and 32 px cover standard and high-DPI browser tabs, and 48 px covers Windows shortcuts. Most browsers automatically request /favicon.ico from a site root, which is why a single .ico remains a reliable fallback even though PNG and SVG favicons are now also supported.

Why is ICO capped at 256×256?

The ICO container records each image's width and height in a single byte, where the value 0 means 256. That makes 256×256 the largest dimension a standard .ico entry can describe, so a larger PPM is downscaled to fit. For a normal full-size viewable picture rather than an icon, convert to PPM to PNG instead.

My PPM is rectangular — will the icon be stretched?

No, and it will not be cropped either. The preset fixes the height and the width follows your source's aspect ratio, so a rectangular PPM produces a rectangular icon at the correct proportions. Windows expects square icons, so start from a square (1:1) image for the cleanest result; a simple logo, letter, or symbol survives the downscale to 16–48 px far better than a detailed photo, which loses fine detail at icon sizes.

Can I set the quality, colour palette, or bit depth?

None of those controls render on an ICO target. The Image Compression group — quality preset and file-size targeting — is hidden, the colour-palette control belongs to GIF output, and the bit-depth control appears only for PPM output, not PPM input. ICO frames are stored as bitmap or PNG data, neither of which has a lossy quality dial, so the resolution preset is the only setting that changes the result.

Can one ICO file hold several sizes at once?

The ICO format is a container that can bundle multiple images at different sizes and colour depths in a single file, and Windows or the browser picks the closest match for the context. This converter writes one image at the preset you choose. To assemble a true multi-size .ico, run the conversion at 256P, 48P, 32P and 16P and combine the outputs in an icon editor such as GIMP or icotool.

Does the PPM's maxval or binary/ASCII variant matter?

Not for the outcome. PPM comes in an ASCII form (P3) and a binary form (P6), and the header declares a maxval — commonly 255 for 8-bit samples, sometimes 65535 for 16-bit. Both variants decode, and 16-bit samples are reduced to standard 8-bit-per-channel colour on the way into the icon, which is what the ICO container stores. At icon sizes that reduction is invisible.

Is the conversion private?

Yes. Your file is uploaded over an encrypted connection, processed on our servers, and deleted automatically after a few hours. There is no sign-up, no watermark, and files are never shared or made public.