CalConverters

Image Format Converter

Drop one or more images below to convert them to PNG, JPEG, WebP, BMP, or GIF. HEIC and AVIF are accepted as sources. Everything runs locally in your browser — nothing is ever uploaded to a server.

Files never leave your device

Drop files here, click to browse, or paste

PNGJPEGWEBPGIFBMPTIFFICODDSQOIPNMAVIFHEIC
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The format above is applied to files as you drop them. After a file is done you can pick a different format for it and press Start to re-convert just that one.

HEIC and HEIF files are decoded on your device by libheif, licensed under the GNU LGPL v3 — loaded only when a dropped file's format calls for it. Licence notice and source

What This Tool Does

This converter changes an image from one file format to another — PNG to JPEG, JPEG to WebP, or any combination among PNG, JPEG, WebP, BMP, and GIF. Drop one file or fifty; each one is decoded and re-encoded in the format you choose, and you download the result with a single click.

Everything happens on your device. There's no upload step, no processing queue on a remote server, and no size limit imposed by a backend. AVIF and HEIC/HEIF sources do have one hard ceiling — 48 megapixels — past which the tool declines rather than risk exhausting your browser's memory; every other format is bounded only by what your browser's memory can hold.

Supported Formats

FormatInputOutputNotes
PNGYesYesLossless, supports transparency. Best for screenshots, logos, and graphics with sharp edges.
JPEGYesYesLossy, no transparency. Smallest files for photos; quality is adjustable.
WebPYesYes (lossless)Modern format, transparency supported. Often smaller than PNG at the same quality.
BMPYesYesUncompressed. Large files, useful for legacy tools that require raw bitmaps.
GIFYesYesLimited to 256 colors. Each conversion here produces a single static frame.
TIFFYes—Input only. Upload a TIFF and convert it to any of the formats above; TIFF isn't offered as an output.
ICOYes—Input only. Windows icon files, including multi-size icons — the entry with the highest color depth is used, with size deciding only between ties.
DDSYes—Input only. DirectDraw Surface textures.
QOIYes—Input only. The "Quite OK Image" format — lossless and very fast to decode.
PNMYes—Input only. The Netpbm family (.pnm, .ppm, .pgm, .pbm).
AVIFYes—Input only. Modern high-efficiency format — decoded by your browser's own image codec rather than the WASM decoder used for the formats above.
HEICYes—Input only. The format iPhones use. Decoded in your browser; 10-bit HEIC is reduced to 8-bit.
HEIFYes—Input only. Same container as HEIC, different extension.

How JPEG Quality Works

JPEG is the only format in this tool with a quality slider (1–100, default 80), because it's the only lossy output here — the others either keep every pixel exactly or aren't re-compressed further. Lower quality values produce smaller files by discarding more fine detail; higher values keep more detail at the cost of file size.

Tip: A quality of 80–85 is usually indistinguishable from the original to the eye while cutting file size substantially. Save quality 95+ for images you plan to zoom into or print.

For a photo you're posting online, 75–85 is a good starting point. For an image that will be edited further or printed large, stay at 90 or above.

Your Files Never Leave Your Device

The conversion runs through a small WebAssembly module loaded into your browser tab. When you drop a file, its bytes are read locally and handed to that module — they're never sent anywhere over the network. Closing the tab discards everything; there's nothing left behind on a server because there was never a server involved in the first place.

If you also need to resize images for a specific platform (App Store icons, social banners, favicons), see the Logo & Image Resizer tools, which use the same on-device approach.

Frequently asked questions

Is this image converter really free?
Yes. There's no sign-up, no watermark, and no limit on how many images you can convert. The tool runs entirely in your browser, so there's no server cost to recoup from you.
Do my images get uploaded anywhere?
No. Every conversion happens locally using WebAssembly running inside your browser tab. Your files never travel over the network, so nothing ever reaches a server.
Can I convert multiple images at once?
Yes. Drop as many files as you like — they're queued and converted one at a time, and each finished file appears as its own downloadable card. Use "Download all" once two or more are ready.
Why is the quality slider only shown for JPEG?
PNG, WebP (lossless), BMP, and GIF in this tool don't discard pixel data, so there's no quality trade-off to tune. JPEG is the one lossy format here, and its slider controls the size-versus-quality balance.
Can I convert a TIFF file?
You can upload a TIFF as your source image, and it will decode and convert correctly. TIFF isn't offered as an output format in this tool, since PNG or WebP cover the same lossless use case with far smaller files and universal browser support.
Why won't Windows open my .heic photo?
HEIC is Apple's default photo format, and most Windows installations have no decoder for it without a paid codec from the Microsoft Store. Converting to JPEG here gives you a file that opens everywhere, and the conversion happens in your browser rather than on a server.
Does converting HEIC to JPG lose quality?
Some, yes, and it's worth knowing why. JPEG is lossy, so re-encoding always discards a little detail — keep quality at 90 or above if that matters. Separately, our HEIC decoder always outputs 8 bits per channel, so a source with greater bit depth (some HDR captures) gets reduced to 8-bit the moment it's decoded — not later, at JPEG's own encoding step, which is where you'd expect it. For an ordinary 8-bit photo neither difference is visible.
Will converting to JPEG add a white background to a transparent PNG?
No — and the actual result is worth knowing. JPEG has no transparency channel, so the conversion simply drops the alpha channel and keeps whatever RGB color already sits underneath it; it does not composite against white or any other background. Many tools produce transparent pixels with the RGB channels already at (0,0,0), because a plain zeroed buffer — what a browser canvas starts a new image from — is exactly that: black with zero alpha. A transparent PNG converted to JPEG here therefore typically comes out with a black background, not white. If you need to keep transparency, convert to PNG or WebP instead.
What happens if a file fails to convert?
That file's card shows an error message and the rest of your batch keeps processing — one bad or corrupted file never stops the others.