ICO to AVIF Converter
Convert ICO files (released 1985 (Microsoft), Container — holds PNG or BMP frames) to AVIF (Lossless + Lossy (AV1-based), typically 30–50% smaller than WebP at the same quality). Runs in your browser — no upload, no signup.
Based on 12,431+ conversions delivered
Teams convert ICO to AVIF mostly for compatibility: AVIF fits Bandwidth-critical pages with modern audiences and runs on Modern browsers (~90% since 2023), while ICO earns its place for Favicons, Windows desktop icons, executable icons. Standardising on AVIF across a pipeline — uploads, a CMS, a design system — removes the friction of mixed formats downstream. Output size depends on the resolution and content of your source image. This converter handles a single file or a large batch the same way, entirely in your browser with no upload. The sections below lay out the format trade-offs, the settings that matter, and the situations where a different target would serve you better.
Looking to programmatically convert ICO to AVIF?
Same engine, available as a JSON API. Drop a file or URL via REST and get the converted output back — no browser, no UI, no rate limits on paid tiers.
Sub-second response on common pairs
Webhook delivery for batch jobs
100+ format pairs supported
ICO vs AVIF — side-by-side
The numbers and capabilities at a glance, so you know what you're trading.
ICO
- Year released
- 1985 (Microsoft)
- Compression
- Container — holds PNG or BMP frames
- Transparency
- Yes
- Animation
- No
- Browser support
- Universal — every browser fetches /favicon.ico
- Best for
- Favicons, Windows desktop icons, executable icons
AVIF
- Year released
- 2019 (AOMedia)
- Compression
- Lossless + Lossy (AV1-based)
- Transparency
- Yes
- Animation
- Yes
- Browser support
- Modern browsers (~90% since 2023)
- Best for
- Bandwidth-critical pages with modern audiences
Heads up before converting ICO → AVIF
What changes — and what your conversion will cost — based on how ICO and AVIF differ.
Older clients may not render AVIF
AVIF support: Modern browsers (~90% since 2023). Modern browsers and OS image viewers handle it natively, but legacy email clients, older CMS thumbnailers, and some print/design tools still don't. Confirm the downstream consumers in your pipeline accept AVIF before swapping at scale, or ship a ICO fallback for the long tail.
Chroma subsampling kicks in
ICO stores full-resolution colour channels. AVIF's default lossy mode subsamples chroma (typically 4:2:0) — half the colour information thrown away to save bytes. The effect is invisible on photos but visible on sharp text, fine lines, and saturated edges (chromatic aberration around text, halos on logos). For UI screenshots and graphic content, prefer a target without chroma subsampling (PNG, WebP-lossless, AVIF 4:4:4) instead.
Best practices for ICO → AVIF
Concrete settings to pick before you convert ICO to AVIF.
- Always preview the AVIF output before bulk-downloading — colour shifts, transparency surprises, and quality artifacts show up in the preview before they ship.
- Strip EXIF metadata if file size or privacy matters — camera GPS coordinates, timestamps, and serial numbers travel inside the image bytes by default.
- For photographic content, target a AVIF quality between 80 and 85 — that's the sweet spot where most encoders stop showing visible artifacts and the file size curve flattens.
- Verify the alpha channel rendered as expected — premultiplied vs straight alpha and edge halos around antialiased pixels are the most common surprises when going to AVIF.
- When converting to AVIF (animated), confirm the frame timing matches your source — some encoders default to a fixed 100ms delay per frame instead of preserving the original timing.
- For web AVIF delivery, encode in sRGB — wider colour spaces (Display P3, ProPhoto) render unpredictably across browsers and email clients.
When NOT to convert ICO → AVIF
Honest cases where this conversion is the wrong call — pick a different format or keep your ICO source.
Skip if your audience uses legacy browsers
AVIF doesn't render on every old browser, email client, or built-in OS viewer. If your traffic includes IE11, legacy Outlook, or older Android WebViews, stay on ICO (or a universal format like JPEG/PNG) — or ship AVIF alongside a fallback via the HTML <picture> element.
Skip if the file is bound for print
AVIF is a delivery-grade web format. Print pipelines (offset, large-format, packaging) expect TIFF, PDF, or high-bit-depth PNG with embedded ICC profiles and a CMYK option. Converting ICO to AVIF for a print job will likely fail prepress checks — keep the original or convert to a print-friendly format instead.
The importance of a good image conversion
Why getting ICO → AVIF right matters more than you think.
Frequently asked
The basics everyone asks before dropping a file.
Convert ICO to other formats