How to convert PNM to HEIC
To convert PNM to HEIC, upload your PNM file, choose HEIC as the output format and press Convert. The finished HEIC file is ready to save to your phone or computer in seconds, free, with no watermark and no sign-up. Your file is deleted from our server about 30 minutes after the conversion.
This free online converter changes PNM images into HEIC files in seconds, with no software to install and no watermark. You can convert several files at once, resize them and choose the quality for formats that support it. Metadata such as location tags is removed from the output for privacy.
Why convert PNM to HEIC?
- About half the size of JPG at the same quality
- Stores depth maps and Live Photos
- Default for iPhone photos
- Works with: iOS, macOS, recent Windows (with extension) and Android 10+
What to expect from this conversion
- PNM is lossless and HEIC is lossy, so the file will usually get much smaller. Use the quality slider to balance size and detail.
- Output is HEVC-based, so check that the devices you share with can open it. If not, JPG is the safer choice.
- Browsers do not display HEIC files, so use it in editors, print workflows or development tools rather than on a web page.
PNM vs HEIC
| Property | PNM | HEIC |
|---|---|---|
| Full name | Portable Anymap | High Efficiency Image Container |
| Released | 1988, Jef Poskanzer (Netpbm) | 2015, MPEG |
| Compression | None (uncompressed) | Lossy |
| Transparency | No | Yes |
| Animation | No | Yes |
| Bit depth | 1, 8 or 16-bit | 8 or 10-bit |
| Shown in browsers | No | No |
| Best for | Unix-style image pipelines; teaching and research | saving space on iPhones; Apple photo libraries |
Steps to convert PNM to HEIC
- Drop your PNM image file onto the converter, or click to choose it.
- Check that HEIC is selected as the target and adjust the options if you want.
- Press Convert, then download your new HEIC file when it finishes.
Tips for the best result
- Use quality 80 to 90 for photos: it is visually close to the original at a much smaller size.
- Set a width if the image will be shown on a small screen, which also reduces the file size.
- Choose a background colour before converting transparent images to a format without transparency.
Frequently asked questions
How do I convert PNM to HEIC?
Drop your PNM files on the converter, confirm that HEIC is the target and press Convert. Download each file or the whole batch as a ZIP.
Is the PNM to HEIC converter free?
Yes. It is free with no watermark, no sign-up and no limit on how many images you convert. The site is supported by ads.
Does converting PNM to HEIC reduce quality?
PNM is lossless and HEIC is lossy, so the file will usually get much smaller. Use the quality slider to balance size and detail. The quality slider only affects formats that use lossy compression.
Will transparency be kept when I convert PNM to HEIC?
PNM images do not contain transparency, so there is nothing to lose. HEIC supports it if you edit the image later.
Which programs open HEIC files?
HEIC files open in iOS, macOS, recent Windows (with extension) and Android 10+.
How many images can I convert at once?
Up to 20 images per batch, each up to 60 MB. Files are deleted from the server about 30 minutes after conversion.