Your files, converted.
Upload nothing.
HEIC photos, iPhone videos, voice memos — converted right on your device. Free, no account needed.
Toss your files in here
🔒 Everything happens on your device — nothing is uploaded, ever.
Images, video & audio. No PDFs or documents. Video support depends on your browser.
Which format do I need?
Start with what you want to do.Share a photo
A practical choice for photos you need to email or open in another app. Transparent areas become white; keep the original for editing.
HEIC → JPEG →Keep text & transparency
Use for screenshots, diagrams, and transparent graphics. PNG preserves the decoded pixels, but a photo may become much larger.
WebP → PNG →Make a website image
Start with the default quality, then compare edges and fine detail. Resizing to the dimensions you actually need can save more than a format change.
PNG → WebP →Save just the audio
Extract a talk or recording from a video. The picture is discarded in the output; the source must contain an audio track.
MP4 → MP3 →What conversion can (and can’t) fix
A larger file isn’t necessarily better. Converting JPEG to PNG or MP3 to WAV cannot restore detail already lost. Keep your original and convert a copy for the app or device that needs it.
Video formats are containers. An MP4 filename doesn’t tell you which codecs are inside. We inspect each file; your browser may support copying a track but not re-encoding it.
Your device does the work. Images above 100 megapixels are refused. Large files can run out of memory below that limit, especially on phones. Try fewer files at a time and keep the tab open.
Some jobs need a different tool. This converter does not handle PDFs, documents, animation preservation, or professional RAW development. Image conversion produces a single still image.
Popular conversions
A small tool that respects your files
🕵️ Your files stay yours
Conversion happens on your device. We don’t receive your files or filenames. Your originals stay unchanged.
🎉 Free, no signup
No accounts, subscriptions, or watermarks. Convert one file or a batch, then download individually or as a zip.
🎬 Useful controls, included
Resize images, adjust quality, trim clips, or extract audio from video. Compare image results before you download.
How converting in the browser works
Online converters have traditionally worked one way: you upload a file, a server somewhere does the work, and you download the result. That means handing your photos, recordings, and documents to a machine you cannot see, and it is why free tiers cap file sizes — bandwidth and processing time cost the operator real money.
Convertmaxxing does the work on your own machine instead. Images run through ImageMagick — the engine that has handled this job on servers since 1990 — compiled to WebAssembly and executing inside your browser tab. Video and audio run on WebCodecs, the same hardware-accelerated pipeline your device uses to record and stream. Both are real conversion engines, not simplified imitations.
Because nothing is uploaded, there is nothing to store, scan, or lose, and no size tier to negotiate. Where the approach has genuine limits — formats we cannot create, browser encoding support that varies, memory ceilings on very large files — we say so plainly rather than shipping a broken file. The full explanation is here, including how to verify the no-upload claim yourself in about ten seconds.
Guides
All guides →- HEIC vs JPEG: Which Format Should You Use?
How Apple’s HEIC compares to JPEG for quality, size, and compatibility — and when converting makes sense.
- WebP vs AVIF vs JPEG XL: Choosing a Modern Image Format
A practical comparison of the three modern image formats: compression, browser support, encode speed, and what to actually use.
- Image Quality Settings Explained: What Does 80% Actually Mean?
What the quality slider really does, why 80 is usually the sweet spot, and why AVIF 55 looks like JPEG 85.
- What Your Photos Reveal: EXIF Metadata and Privacy
GPS coordinates, timestamps, and device details hide inside your photos. What EXIF metadata is and how to strip it.
- PNG vs JPEG: When to Use Each Format
Photos vs graphics, transparency, artifacts, and file size — a clear answer to the classic format question.
- Containers vs Codecs: Why Your Video Won’t Play
MP4, MOV, MKV, WebM — the file extension describes the box, not the video inside. Understanding the difference explains almost every playback problem.
- Camera RAW Explained: What’s Actually Inside a CR2, NEF, or ARW
RAW files are not images — they are sensor measurements waiting to be interpreted. What that means for editing latitude, colour, and converting to JPEG.
- MP3, WAV, M4A and FLAC: Choosing an Audio Format
What lossy compression actually throws away, which bitrate is genuinely enough, and why converting between lossy formats costs you twice.
- How File Conversion Works Without Uploading Anything
WebAssembly and WebCodecs let a browser tab run the same conversion engines a server would. What that means for privacy, speed, and the limits you will hit.
Common questions
- Are my files really not uploaded anywhere?
- Correct, and you can verify it rather than take our word for it. Conversion runs inside your browser using WebAssembly and your browser’s own video pipeline, so there is no upload step at all. Open your developer tools, switch to the Network tab, and run a conversion — you will see the page and the conversion engine load, and no request carrying your file.
- Is there a file size limit?
- There is no limit imposed by us, because there is no server paying for bandwidth or CPU time. The practical ceiling is your own device: WebAssembly memory caps out around 4 GB, so extremely large images can exhaust it. When that happens you get an honest error rather than a corrupted file.
- Do I need to create an account?
- No. There are no accounts, no email collection, no newsletter, and no free tier with a paywall behind it. Open the page, drop in files, download the results.
- Which formats can Convertmaxxing not create?
- HEIC cannot be created — no HEIC encoder is available to our engine for patent reasons, the same reason browsers do not display HEIC natively. Camera RAW formats (CR2, CR3, NEF, ARW, DNG) are read-only because RAW data can only come from a camera sensor. MOV, MKV, and ProRes are read-only too, since MP4 is the more compatible destination in every case. There is no PDF support at all.
- Why did my video conversion fail when the same file worked elsewhere?
- Video encoding uses your browser’s own hardware pipeline, and support varies between browsers and platforms — a combination available in Chrome may be missing in Firefox on the same machine. Rather than producing a file that will not play, the converter probes what your browser can actually encode and tells you when something is unavailable. Converting to MP3 or WAV always works, since those encoders ship with the site.
- Does converting to a lossless format restore lost quality?
- No. Converting a JPEG to PNG, or an MP3 to WAV, preserves exactly what is already in the file — artifacts included — in a larger container. It is genuinely useful before a round of editing, because it stops further degradation accumulating, but detail discarded by an earlier lossy save cannot be recovered by any tool.
All conversions
Browse formats →- HEIC → JPEG
- HEIC → PNG
- HEIC → WebP
- PNG → WebP
- WebP → PNG
- PNG → JPEG
- JPEG → PNG
- JPEG → WebP
- WebP → JPEG
- PNG → AVIF
- JPEG → AVIF
- WebP → AVIF
- AVIF → JPEG
- AVIF → PNG
- AVIF → WebP
- JPEG → JPEG XL
- JPEG XL → JPEG
- PNG → JPEG XL
- JPEG XL → PNG
- TIFF → JPEG
- TIFF → PNG
- PNG → TIFF
- BMP → JPEG
- BMP → PNG
- PNG → ICO
- JPEG → ICO
- ICO → PNG
- DNG → JPEG
- CR2 → JPEG
- CR3 → JPEG
- NEF → JPEG
- ARW → JPEG
- MOV → MP4
- WebM → MP4
- MP4 → WebM
- MKV → MP4
- ProRes → MP4
- MP4 → MP3
- MP4 → WAV
- WAV → MP3
- MP3 → WAV
- M4A → MP3