Add your PBM file
Drop one or more .pbm files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
PBM to PGM
Converting a .pbm image to .pgm re-encodes the pixels for a different balance of size, quality, and support. Free, private, and validated — the file never leaves your browser.
Private for supported formats — processed in your browser
Runs on your deviceConvert supported files
Drop PBM files here
Batch files can each use a different output. Nothing uploads for local conversions.
Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.About converting Portable bitmap to Portable graymap
Converting a .pbm image to .pgm re-encodes the pixels for a different balance of size, quality, and support. A .pbm file is a Portable Bitmap: the simplest image format in common use, storing exactly one bit per pixel — black or white, with no grey and no colour. It carries a two-character magic number, the width and height, and then the pixels, and nothing else.
A .pgm file is a Portable Graymap: a single-channel greyscale image storing one intensity value per pixel, with the maximum value declared in the header. It is the middle rung of the Netpbm ladder — richer than a one-bit bitmap, simpler than a colour pixmap. For this route the practical draw is raw samples in a declared range — no codec, no colour management, nothing to misinterpret and supports 16-bit depth, which most consumer formats do not — balanced against uncompressed, so files are large relative to PNG for the same data, which is worth knowing before you commit a large batch.
Why convert PBM to PGM?
The practical trigger for this conversion is usually a mismatch: with .pbm, one bit per pixel — no grey, no colour, no transparency. Switching to .pgm buys you raw samples in a declared range — no codec, no colour management, nothing to misinterpret, which is why it is the better fit for machine vision and image-processing pipelines that operate on intensity alone. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
PBM vs PGM at a glance
| Aspect | Portable bitmap (.pbm) | Portable graymap (.pgm) |
|---|---|---|
| Format type | Lossless — every pixel or sample is preserved exactly | Lossless — every pixel or sample is preserved exactly |
| How it stores data | two encodings share the extension: P1 stores pixels as ASCII 0 and 1 characters, P4 packs eight pixels into each byte | p2 stores samples as whitespace-separated ASCII integers; P5 stores them as raw bytes |
| Strongest at | masks, stencils and other genuinely two-tone raster data | machine vision and image-processing pipelines that operate on intensity alone |
| Weak spot | one bit per pixel — no grey, no colour, no transparency | uncompressed, so files are large relative to PNG for the same data |
| Metadata | none beyond optional # comments in the header. There is no colour profile, no EXIF and no timestamp; a PBM carries dimensions and pixels and nothing else | none beyond header comments. No colour profile, no EXIF, no acquisition metadata — anything an instrument recorded alongside the pixels has to travel in a separate file |
Pick PGM as the output
Select .pgm in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if PGM is selectable, the route is real and validated.
Convert on your device
Press Convert. Decoding and re-encoding happen on your device using the browser's native image pipeline and hand-tuned encoders.
Verify and download
Each result is signature-checked before the download unlocks, so a failed encode can never masquerade as a valid PGM file. Outputs keep the original filename with the .pgm extension.
PBM to PGM questions, answered
Will converting PBM to PGM lose quality?
Since pbm is lossless-oriented and pgm is lossless-oriented, the conversion preserves the source content exactly as stored; no additional compression pass is applied beyond what .pgm itself requires.
Is it private to convert PBM files here?
Yes — the .pbm file is processed inside your browser tab and never uploaded. Decoding and re-encoding happen on your device using the browser's native image pipeline and hand-tuned encoders. Close the tab and the file is gone from memory.
Where will the PGM file work?
Standard in scientific and machine-vision toolchains — OpenCV, ImageMagick, MATLAB and Netpbm all read it — and absent from consumer software and browsers. Novus Convert decodes both ASCII and binary PGM locally, honours the declared maximum value when scaling to 8-bit output, and converts to the standard raster formats.
Will the PGM file be bigger or smaller than my PBM?
It depends on the content: p2 stores samples as whitespace-separated ASCII integers; P5 stores them as raw bytes. Convert one representative file first and compare before batch-processing a large set.
What happens to the metadata in my PBM file?
In .pbm, none beyond optional # comments in the header. There is no colour profile, no EXIF and no timestamp; a PBM carries dimensions and pixels and nothing else. Re-encoding through the browser pipeline does not carry embedded metadata into the output, which doubles as a privacy scrub — check the exported file if you specifically need tags preserved.
Can I convert PGM back to PBM?
Yes — the reverse route exists as a separate tool. Bear in mind that round-tripping .pbm → .pgm → .pbm is not a perfect undo when any lossy step is involved; keep your original if fidelity matters.