TL;DR
We launched Convert — a small set of file converters that run entirely inside your browser. Nothing is uploaded, there is no sign-up, no file-count cap, and no watermark. Four tools at launch: PNG to ICO, compress an image to an exact KB size, HEIC to JPG, and AVIF to JPG.
Every online file converter works the same way
You search for "png to ico". You land on a site. You pick your file. Then:
- The file uploads to a server somewhere.
- You wait in a queue behind other people's files.
- The server converts it and gives you a download link.
- Somewhere in there you hit a limit — two files free, 5 MB maximum, sign up to continue, or a watermark on the result.
Step 4 is not malice. It is arithmetic. Running conversions on a server costs money per file: bandwidth in, CPU to convert, storage while the result waits, bandwidth back out. Someone has to pay for that, so the free tier is deliberately uncomfortable. The caps, the sign-up wall, the watermark, and the upgrade button all exist because of a decision made in step 1.
And steps 1 through 3 mean your file — a passport scan, a signed contract, a photo of your kid — sits on a machine you do not control, under a retention policy you did not read.
The upload is the slow part
Here is the thing that surprised us when we started measuring: for the kinds of conversions most people actually search for, the conversion itself is trivial. The upload is the bottleneck.
Turning a PNG into a multi-size .ico is a few milliseconds of work. Compressing a JPEG to land under 100 KB is a handful of encode passes. These are not hard computational problems. They only feel slow because the file has to make a round trip across the internet first.
Modern browsers can do all of that work locally. Canvas can decode and re-encode images. Web Workers keep heavy work off the interface so the page never freezes. OffscreenCanvas lets that work happen on a background thread entirely. The capability has been sitting there for years.
So we built the obvious thing: convert the file where it already is.
What we built
Four tools at launch. Each one is a job people search for constantly and get a mediocre experience for.
Make a proper multi-size favicon
Most "favicon generators" hand you a single 32×32 image and call it done. A real .ico file is a container that holds several resolutions at once, and Windows and browsers pick whichever one fits the context — the tab, the bookmarks bar, the desktop shortcut, the taskbar.
PNG to ICO writes a genuine multi-resolution .ico with 16, 32, 48, 64, 128, and 256-pixel versions embedded, and you choose which sizes go in. There are matching pages for JPG to ICO, any image to ICO, and PNG to favicon if that is how you think about the task.
Hit an exact file size
This is a strangely common and strangely underserved problem. Government portals, university applications, job boards, and exam registration sites routinely say "photo must be under 100 KB" and then reject anything larger without telling you how much to cut.
Most compressors give you a quality slider and let you guess. Compress image to KB takes the target instead: you say 100 KB, it binary-searches encoder quality — and downscales if it has to — until the result lands under your number. There are direct pages for 20 KB, 50 KB, 100 KB, and 200 KB.
Open iPhone photos anywhere
Since 2017, iPhones have saved photos as HEIC by default. It is a genuinely better format — roughly half the size of JPEG at equivalent quality. It is also the reason a photo you AirDropped to a colleague will not open on their Windows laptop, will not attach to some web forms, and will not import into older software.
HEIC to JPG converts them, in batches, with no file-count cap, and zips the results. There are dedicated pages for batch conversion and for opening HEIC on Windows, which is where most of the pain actually lives.
Open AVIF images
AVIF is the newer web image format, and it is spreading fast because it compresses beautifully. The side effect is that you right-click, save an image, and then nothing on your computer will open it. AVIF to JPG fixes that.
What this looks like in practice
A concrete example, because the exact-size tool is the one people find hardest to picture.
Say you are filling in an online application. The form says: passport photo, JPG, under 100 KB. Your phone took a 4 MB photo. You have no idea what quality setting turns 4 MB into 99 KB, and the form will not tell you how close you got — it just rejects the file.
The usual path is a quality slider and four or five rounds of guessing. Export at 60%, check the size, still too big, try 40%, now it looks terrible, try 50%, upload, rejected, try again.
The tool inverts that. You drop the photo, type 100, and it works backwards from your number: it encodes, measures the result, adjusts quality, and repeats — narrowing in on the largest file that still fits under your limit. If quality alone cannot get there, it reduces the dimensions too. You get the best-looking image that satisfies the constraint, in one step, and the row tells you exactly what you ended up with: 44 KB · ≤ 50 KB ✓.
The same inversion applies elsewhere. You do not want "a favicon", you want an icon that stays sharp in a browser tab and on a desktop shortcut. You do not want "a converted photo", you want one your colleague on Windows can actually open. Each tool is built backwards from the outcome, not forwards from the file format.
The honest part: what is instant and what is not
We could tell you every tool is instant. Three of them genuinely are, and one deserves an asterisk. We would rather set the expectation correctly than have you think the page is broken.
PNG to ICO, compress-to-KB, and AVIF to JPG are effectively instant. Sub-second on any reasonably modern machine. Your browser has native, hardware-accelerated support for those formats, so there is nothing to wait for.
HEIC is more complicated. Safari, iOS, and macOS can decode HEIC natively, so on an iPhone or in Safari on a Mac, conversion is essentially instant. Chrome, Edge, and Firefox cannot decode HEIC at all — no native support, none planned publicly — so on those browsers we fall back to decoding it in software, using a WebAssembly build of the libheif library. That works, and the output is a full-resolution JPEG, but a 12-megapixel photo takes roughly 20 to 30 seconds.
That is a real trade-off and we are not going to hide it behind the word "instant". What we can say honestly is that there is no upload wait — nothing leaves your device and nothing comes back, which is the part every other converter makes you sit through. On a big batch in Chrome, the honest pitch is not "fast", it is "there is no two-file cap and no sign-up".
If you are converting a lot of iPhone photos and you have a Mac or an iPhone handy, use Safari. It is dramatically quicker.
What "nothing uploaded" actually means
This claim is easy to make and rarely verified, so here is precisely what it means for us.
When you drop a file on any of these tools, it is read into your browser's memory and processed there. No request carries the file anywhere. You can check this yourself: open your browser's developer tools, switch to the Network tab, and convert something. You will see no upload.
There is exactly one thing that leaves your device, and we would rather tell you about it than have you find it: an anonymous counter. When a page loads or a conversion finishes, we send a tiny event that says something like "someone used the HEIC tool and it succeeded". It contains no file, no filename, no file contents, no account, no cookie, and no visitor identifier. We cannot tell how many unique people used the site, only how many conversions happened. That is a deliberate limitation, and it is documented on the privacy page.
The site is also covered by a Content Security Policy that restricts where the page is allowed to send anything at all — a second line of defence, so a bug or a compromised dependency cannot quietly start shipping your files somewhere.
Who this is for
- Developers and designers who need a real multi-size favicon and do not want to install anything.
- Anyone fighting an upload form with a hard KB limit — applications, exam portals, government sites.
- iPhone owners who need to send photos to someone on Windows, or upload them to a site that rejects HEIC.
- People who would simply rather not hand a personal document to a stranger's server to perform a ten-millisecond task.
If your work is PDF-shaped rather than image-shaped, our extensions cover that side: Convert: Web to PDF saves webpages as clean PDFs, and Convert: Anything to PDF turns images, CSV, HTML, and Markdown into PDFs. Same principle in both: the conversion happens on your machine.
What is next
We deliberately launched narrow. Four tools, each one aimed at a job people genuinely search for, rather than a wall of two hundred format pairs where half quietly fail.
What we are looking at next: a live preview of each icon size before you download, more image format pairs, and translations — the extensions already ship in fourteen languages and the converter site should follow.
If a conversion you need is missing, or one of these produces a file that does not work where you need it to, tell us. That is the most useful thing you can send us right now.
Frequently asked questions
Is it really free, or is there a catch later?
It is free and unlimited, with no sign-up and no watermark. The reason we can say that without an asterisk is that conversions cost us nothing — they happen on your computer, not on a server we rent. There is no per-file cost to recover, so there is no free tier to outgrow.
Are my files uploaded anywhere?
No. Files are read into your browser's memory and converted there. Nothing carrying your file is sent anywhere, and you can verify it in the Network tab of your browser's developer tools. The only thing transmitted is an anonymous event counter with no file data, no filename, and no visitor identifier.
Why does HEIC take so long in Chrome?
Chrome, Edge, and Firefox have no built-in HEIC decoder, so the page decodes the photo in software using a WebAssembly build of libheif. That takes roughly 20 to 30 seconds for a full-resolution 12-megapixel photo. Safari, iOS, and macOS decode HEIC natively, so the same photo converts almost instantly there. If you have an iPhone or a Mac, use Safari for large batches.
How many files can I convert at once?
As many as you like. There is no file-count cap and no size limit beyond what your device's memory can hold. Batch results download together as a single zip. Very large batches on a phone are best done in smaller groups, simply to keep memory comfortable.
Why is my converted JPG bigger than the HEIC I started with?
Because HEIC is a more efficient format. A HEIC photo is roughly half the size of a JPEG at the same visual quality, so converting to JPEG usually increases the file size. That is expected and not a fault in the conversion. If you need a smaller file, run the result through the compress-to-KB tool and set a target.
What is a multi-size .ico and why does it matter?
An .ico file can hold several resolutions in one file. Windows and browsers pick whichever fits the context — a 16-pixel version for a browser tab, a 256-pixel version for a large desktop icon. If your .ico contains only one size, everything else gets scaled from it and looks soft or muddy. Our converter embeds several resolutions so each context gets a version drawn for it.
Does this work offline?
Once the page has loaded, the conversion itself needs no connection, because it runs locally. You do need a connection to load the page the first time. The HEIC tool additionally downloads its decoder the first time you use it in a browser without native HEIC support.
Do I need to install an extension for this?
No. The converter site is an ordinary website — nothing to install. Our browser extensions are a separate product for PDF work, and are optional.