PGM to HDR Converter
Processing entirely on your device — large files may take a moment.
PGM is netpbm's grayscale format — 8 or 16-bit samples, ASCII or binary, zero compression. Computer-vision research and image-processing courses live on it. Converting HDR to PNG produces a tone-mapped preview usable in any image viewer.
Because the whole conversion happens on your device, it is instant, unlimited and genuinely private — no accounts, no watermarks, no files on anyone's server. Multiple files are converted in one go.
How to convert PGM to HDR
- 1
Select your files
Drag & drop your PGM files onto the area above, or click to browse. You can add multiple files at once for batch conversion.
- 2
Convert instantly
Click "Convert to HDR". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted HDR file individually, or grab everything at once as a ZIP archive.
About the PGM format
PGM is netpbm's grayscale format: a two-line text header, then raw 8 or 16-bit luminance samples with no compression and no metadata. That raw honesty made it the default exchange format of computer-vision research, image-processing coursework and any pipeline where "what you read is exactly the pixel value" matters.
Converting PGM to PNG or JPG just normalizes it for humans; converting back down preserves every value bit-exactly when the pipeline needs numbers, not pictures.
+Strengths
- ✓Bit-exact pixel values, no color management surprises
- ✓16-bit depth support
- ✓Trivially parseable
!Limitations
- −No compression — large files
- −Grayscale only
- −No embedded metadata
About the HDR format
HDR (Radiance RGBE) is the veteran high-dynamic-range format of lighting research and 3D rendering: pixels stored as a shared 8-bit exponent plus per-channel mantissas, letting one file hold both a sun and a shadow with no clipping. HDRI environment maps for 3D scenes are almost always HDR files.
Standard image viewers show it badly or not at all, because the values can exceed what a screen can display. Converting HDR to PNG tone-maps the file into an 8-bit preview — good for quick inspection, though the floating-point original remains the render-grade master.
+Strengths
- ✓True high-dynamic-range values
- ✓The standard of HDRI environment maps
- ✓Compact for its precision
!Limitations
- −Not display-ready — needs tone mapping
- −Viewer support is scarce
Why convert PGM to HDR?
Converting makes sense where the strengths of HDR meet what PGM cannot give you. True high-dynamic-range values Meanwhile No compression — large files One pass through the converter above puts your file on the right side of that trade-off.
Frequently asked questions
Is this PGM to HDR converter really free?
Yes — completely free, with no sign-up, no watermark and no daily conversion limits. The site is supported by advertising.
Are my files uploaded to a server?
No. The conversion runs entirely inside your browser using WebAssembly, so your files never leave your device — that is what makes it instant and private.
Does it work on Windows, Mac, iPhone and Android?
Yes. Anything with a modern browser works: Windows, macOS, Linux, Android and iOS. No software installation is required.
Will I lose quality converting PGM to HDR?
No — HDR is a lossless format, so every pixel of the converted image matches your original PGM file. You can also adjust the quality/size balance before converting when the target format supports compression.
Will transparent areas survive the conversion to HDR?
Transparency is kept whenever HDR actually supports an alpha channel. If the target format has none (like JPG), transparent areas are flattened onto a white background — that is a property of the format, not of this tool.
Can I convert several PGM files at once?
Yes — drop as many files as you like into the tool and they are converted in one batch. When more than one file comes out, everything is bundled into a ZIP for a single download.