ICO to HEIC Converter
Convert ICO to HEIC in your browser. ICO files usually come from website favicons, Windows programs and installers; HEIC is the better fit for storing photos on Apple devices. You get a HEIF file whose picture is JPEG-compressed rather than HEVC, because no HEVC encoder runs in a browser. Nothing is uploaded.
- Processed locally
- No upload, no wait
- No sign-up
- No watermark
Drop images here
or choose files · paste with Ctrl/⌘ V
ICO expected · other image formats also work
How to use ICO to HEIC
- 1
Add your ICO files: drop them here, choose them, or paste from the clipboard.
- 2
Pick the colour that replaces transparent areas, since HEIC has none.
- 3
Click Convert. Each file is decoded and encoded in a background thread on this device.
- 4
Download the .heic files one at a time or together as a ZIP.
Why use Aback Images for ico to heic
Where the HEIC goes next
HEIC opens in Apple devices, recent Android phones, and Windows with the HEIF and HEVC extensions.
HEIC next to ICO
A lossy HEIC usually comes out far smaller than the ICO, which stores each size stored as a headerless BMP or as a complete PNG.
The first lossy pass
The ICO holds 1 to 32 bits per pixel, set per size with nothing discarded yet. This conversion is the first lossy encode these pixels see, and hard edges and flat colour show it first.
Processed on your device
Your images are decoded, edited and encoded inside this browser tab by Web Workers. Nothing is uploaded to a server.
ICO vs HEIC
What changes from ICO to HEIC
Encoding: the ICO uses each size stored as a headerless BMP or as a complete PNG; HEIC uses lossy HEVC (H.265) intra coding, on iPhones as a grid of 512×512 tiles, and the download is a HEIF file whose picture is JPEG-compressed rather than HEVC, because no HEVC encoder runs in a browser.
Bit depth: 1 to 32 bits per pixel, set per size in the ICO; HEIC allows 8 or 10 bits per channel, and the HEIC written here has 8 bits per channel.
Colour: RGB or a palette, per image in the ICO; HEIC supports YCbCr, usually tagged Display P3 on iPhones, written here as 8-bit sRGB.
Transparency: the ICO stores it as 8-bit alpha in 32-bit and PNG entries, or a 1-bit mask in old icons; HEIC could hold it as an auxiliary image item, rarely used by cameras, but this writer flattens it, so transparent areas are filled with the colour you choose.
Other images: the ICO can hold several sizes of the same picture, typically 16, 32, 48 and 256 px; only the main image is converted.
Metadata: the ICO can carry only a directory of the sizes inside, with no EXIF; HEIC can carry EXIF, XMP and an ICC profile, stored as items, but nothing is copied across.
About ICO
ICO is a container that bundles several sizes of the same icon (16, 32, 48, 256 px) into one file. It is still the most compatible format for website favicons and Windows app icons.
An ICO starts with a 6-byte ICONDIR (type 1 for icons) and a 16-byte entry per image giving width, height, colour count and offset. Each image is either a BMP without its file header plus an AND mask, or a complete PNG.
ICO files usually come from website favicons, Windows programs and installers.
About HEIC
HEIC is the default photo format on iPhones and many Android phones. It is about half the size of JPEG, but Windows, many websites and older software cannot open it without converting.
A HEIC is a HEIF file (ISO base media boxes with the brand 'heic'). iPhone photos store the picture as a grid of 512×512 HEVC tiles that the decoder stitches together, with the thumbnail, depth map and HDR gain map as further items.
When converting ICO to HEIC makes sense
HEIC is the better choice for storing photos on Apple devices, while ICO suits favicons and Windows icons.
HEIC strengths: About half the size of JPEG; Stores depth maps, Live Photos and HDR. Drawbacks to weigh: Not supported by most websites and Windows apps; Patent-encumbered codec.
Limitations
- The largest image in the icon is the one converted; smaller sizes that were hand-tuned for 16 px are not carried over.
- Icons are small and hard-edged, so lossy encoders show ringing around the outline quickly.
- The file is a valid HEIF, but its picture is JPEG-coded rather than HEVC, so apps that expect HEVC (Apple Photos, Windows' HEVC extension) may not open it.
- The picture inside is JPEG-coded, so the file is about the size of a JPG at the same quality rather than the half size of a camera HEIC.
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Frequently asked questions
Does converting ICO to HEIC lose quality?
HEIC is lossy, so detail the eye barely notices is discarded to save space. Not carried over: any several sizes of the same picture.
What happens to transparency when converting ICO to HEIC?
ICO stores transparency as 8-bit alpha in 32-bit and PNG entries, or a 1-bit mask in old icons. HEIC has no alpha channel, so transparent pixels are composited onto a solid colour, white unless you pick another. To keep transparency, convert to PNG, WebP or AVIF instead.
Will the HEIC open in Apple Photos?
Not always. The file is a valid HEIF container, but its picture is JPEG-compressed rather than HEVC, because no HEVC encoder can run in a browser. libheif-based apps such as GIMP, darktable and ImageMagick open it; Apple Photos and Windows' HEVC extension expect HEVC and may refuse it. For an iPhone, JPG is the safer choice.
Which apps open HEIC files?
Apple devices, recent Android phones, and Windows with the HEIF and HEVC extensions. It opens in Safari on recent Apple systems; other browsers do not display it.
Are my images uploaded anywhere?
No. Processing happens inside your browser with WebAssembly and Web Workers. The site only downloads the app code and codecs; your files never leave your device. You can confirm this with the live upload counter on the tool, or in your browser's network panel.
Can I process many files at once?
Yes. Drop a whole selection or folder. Files are processed in parallel on several worker threads, each result can be downloaded on its own, and everything can be saved as one ZIP.
Is it free? Is there a file limit or watermark?
It is free with no account, no watermark and no daily limit. The only limit is your device's memory: very large images (over roughly 100 megapixels) may be refused to keep the tab from crashing.