CGM to PGM Converter

Convert CGM metafiles to PGM grayscale images online

Drop files here. 1 GB maximum file size or Sign Up
to
Facebook Amazon Microsoft Tesla Nestle Walmart L'Oreal

Clean Grayscale

PGM captures grayscale nuance from your CGM drawings. Technical diagrams with shading translate faithfully into this portable format.

Web-Based Process

No software downloads or installations. The CGM to PGM converter runs entirely in your browser — any device, any OS.

Server-Side Speed

Conversion processing happens on Convertio servers. Your machine stays free while your PGM file is generated remotely.

How to convert CGM to PGM

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose pgm or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your pgm file right afterwards

About formats

CGM (Computer Graphics Metafile) is a vector graphics standard defined by ISO 8632, first published in 1987 and developed through the ISO/IEC JTC 1/SC 24 committee. The standard defines a device-independent format for storing and transferring two-dimensional vector graphics, raster images, and text. CGM supports three encoding methods: character encoding (compact text representation), binary encoding (efficient machine-readable form), and clear-text encoding (human-readable for debugging). The format describes graphical primitives including polylines, polygons, ellipses, circular arcs, splines, and text with associated attributes for color, line style, fill patterns, and clipping boundaries. CGM found its strongest adoption in technical documentation, particularly in aerospace, defense, and industrial sectors where long-term archival and precise technical illustration are critical. One advantage is formal standardization — as an ISO standard, CGM provides vendor-neutral, specification-driven interoperability guaranteed across compliant implementations. The format's adoption in specialized industries is another practical strength: WebCGM, a W3C profile of CGM, became the mandated illustration format for interactive electronic technical manuals in the aerospace industry (ATA iSpec 2200), ensuring CGM's continued relevance in aviation maintenance documentation. While general-purpose vector work has moved to SVG and PDF, CGM persists in regulated industries where certified, standards-based graphics interchange is mandatory.
Initial release: 1987
PGM (Portable Graymap) is the grayscale member of the Netpbm image format family, created by Jef Poskanzer in 1988 as part of the Pbmplus toolkit for Unix systems. PGM stores single-channel intensity images where each pixel holds a gray value from 0 (black) to a user-specified maximum (typically 255 for 8-bit or 65535 for 16-bit). The format exists in ASCII (magic number P2), where pixel values are written as decimal text numbers separated by whitespace, and binary (magic number P5), where values are stored as raw bytes. Both variants begin with a header specifying the magic number, width, height, and maximum gray value. PGM was designed as the grayscale intermediate in Netpbm's convert-process-convert pipeline philosophy: source images from any format are converted to PGM, processed using Netpbm's extensive command-line tool library, then converted to the target format. One advantage is format transparency — the ASCII variant makes image data directly readable by humans and trivially processable by text tools like awk and grep, invaluable for debugging and education. The scientific and computer vision community's adoption is another strength: PGM's straightforward single-channel representation makes it a natural format for image analysis algorithms, and many academic papers and course materials use PGM examples. The format is supported by ImageMagick, GIMP, and countless image processing libraries, and remains standard input for many research tools and benchmarks.
Developer: Jef Poskanzer
Initial release: 1988

Frequently Asked Questions

Why convert CGM to PGM?

PGM is a portable grayscale format perfect for image processing pipelines. CGM to PGM rasterizes technical drawings into a lightweight grayscale form.

What programs handle PGM files?

GIMP, IrfanView, XnView, ImageMagick, and the Netpbm toolkit all open and process PGM files without issues.

Is PGM a compressed format?

PGM can be stored in plain text or binary form but uses no lossy compression. Grayscale values are preserved accurately.

Does CGM to PGM retain shading?

PGM captures grayscale gradients. Any shading in your CGM file converts to corresponding gray levels in the output.

Is this conversion free?

Standard CGM to PGM conversion is free. Premium subscriptions extend limits for bulk or professional workflows.