PFM file format: what it is and how to use it

PFM is the Portable Float Map, the Netpbm family's high-dynamic-range member, storing raw 32-bit float pixels for HDR and scientific imaging. Learn when to use it and what to choose instead.

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What is a PFM file?

A .pfm file is an image in Portable Float Map, the Netpbm family's HDR member: a header (PF color or Pf grayscale), a scale factor, then 32-bit little-endian floats per channel. It carries real radiance values without quantization, which is why optical-flow datasets, HDR research and render passes keep showing up as .pfm.

When should you use PFM?

  • Float-precision image data: depth, flow, HDR luminance without compression loss.
  • Research pipelines: the format many vision datasets are published in.
  • Simple HDR storage: trivially parsed, exactly as stored.

When is another format a better fit?

For VFX pipelines EXR is the professional standard with channels and compression. For lighting maps .hdr is more compact; for display images PNG or JPG, since PFM is data, not pictures.

The short version: PFM is the float-data Netpbm member: a research and pipeline format, never a delivery one.

How to open a PFM file

On Windows

Double-click the file, or open it with GIMP.

In your browser

Open PFM files right in a browser tab or with the dexrr viewer. No install, no upload.

Also opens in

  • Netpbm tools
  • ImageMagick
  • GIMP

View or convert PFM files

A quick preview or a new format. No install, no upload.

View PFM files Preview and inspect PFM files Convert to PFM Turn files into PFM PFM to PAM Portable Arbitrary Map PFM to PNM Portable Any Map PFM to EXR OpenEXR PFM to HDR Radiance HDR (RGBE)

PFM technical details

Full name
Portable Float Map
Extensions
.pfm
MIME type
image/x-portable-floatmap
Magic bytes
50 46 / 50 66 (PF/Pf)
Compression
None (uncompressed)
Developer
Netpbm community

PFM questions, answered

How do I open a .pfm file?

ImageMagick, OpenCV, Blender, MATLAB and HDR tools read it; OS viewers do not. dexrr displays and converts pfm files directly in your browser.

Can I convert PFM files online?

Yes, dexrr converts pfm locally in your browser: PFM to PNG with tone mapping or PFM to EXR for production use.

Is PFM better than EXR?

For raw float storage it is simpler; for production, EXR wins with channels, layers and compression. Different levels of ambition.

Why does my .pfm look black or blown out?

It stores scene-referred floats. Apply a stretch or tone map before judging the image on a display.

Is the PFM format outdated?

Stable and niche: a data format kept alive by research datasets and HDR pipelines.