Privacy-first file tools that run in your browser.

How ConvertUnlimited works

ConvertUnlimited is a browser-native utility site for common image, PDF, and developer tasks. For supported image workflows, the selected file is read by the browser, decoded with browser APIs such as Canvas, re-encoded in the selected output format, and offered back as a download from the same tab.

This local-processing model means ConvertUnlimited does not provide a server-side upload endpoint for supported image conversion flows. It does not mean every browser can process every file: very large images, unsupported formats, limited memory, or browser encoder differences can still affect results.

Conversion uses your computer's CPU and memory. For most laptops, dragging in 30–80 photos at typical phone-camera resolutions feels instant. Very large batches — hundreds of high-megapixel images at once — will use more RAM and may slow your machine briefly while they encode. We suggest queuing roughly 50 images at a time as a comfortable middle ground, but the tool doesn't enforce a limit; use whatever your machine handles cleanly. See Tips for big batches for guidance on larger jobs.

Start with the tools index when you need a specific workflow, or read how local browser processing works before using the site with sensitive files.

Image format guide

Different image formats trade off file size, quality, transparency, and compatibility. Here's a quick rundown of the formats ConvertUnlimited reads and writes, and when to choose each.

WebP

Google's modern image format. At the same visual quality, WebP files are typically 25–35 % smaller than JPEG and 50 % smaller than PNG, and they support transparency. WebP is supported by every current browser, so it's the best default for the web. Choose WebP when you want maximum savings and your audience views images in a browser.

JPEG

The universal photo format. JPEG is lossy (it discards information to shrink the file), doesn't support transparency, and is supported absolutely everywhere — email, social media, printers, decade-old phones. Choose JPEG for photos when you need maximum compatibility, or when you're embedding into a system you don't control.

PNG

Lossless and supports transparency. PNG is ideal for screenshots, logos, icons, and any image with sharp edges or solid-colour regions, because it compresses those without artefacts. The trade-off is file size: PNGs of photos are several times larger than the equivalent JPEG or WebP. Choose PNG when you need transparency or when image fidelity matters more than size.

GIF

A legacy format from the 1990s. It supports basic animation but compresses with a 256-colour palette, so it looks blocky on photos. For new work, prefer WebP for static images and MP4 / WebM for animation. ConvertUnlimited reads GIFs and converts the first frame — for animated GIFs, only that first frame is kept.

SVG

A vector format made of XML drawing commands. ConvertUnlimited reads SVGs and rasterises them (turns them into pixel images) at the SVG's natural dimensions. Once a vector has been rasterised you can't scale it back up cleanly, so only convert SVG when you specifically need a raster output — for example, embedding a logo into a JPEG product photo.

BMP

An uncompressed bitmap format. BMPs are huge for what they store. There's almost never a reason to keep an image as BMP today — convert to WebP, JPEG, or PNG and save 80–95 % of the disk space.

Choosing the right quality

The quality dropdown only applies to lossy formats (WebP and JPEG). PNG is lossless, so the dropdown is automatically disabled when PNG is selected. The four presets translate roughly to:

Original (1.0). Visually identical to the source for most images. Files are still smaller than the input because modern JPEG and WebP encoders are more efficient than older sources, but you give up almost no fidelity.

High (0.9). Negligible visual difference for most photos. Good default for hero images, photography, anything where quality matters.

Recommended (0.75). The sweet spot for web use. Files are typically 30–50 % smaller than High with no loss visible at normal viewing sizes. Use this for blog posts, product galleries, social media.

Compact (0.5). Aggressive compression. Best for thumbnails, image grids, or when you need to email a folder of photos and bandwidth is the bottleneck. You'll notice softness in fine detail, especially on text-heavy or high-contrast images.

Tips for big batches

A few things to know when you're converting more than a handful of files:

Batch size. We recommend up to ~50 images at a time as a comfortable starting point. Most laptops handle 100–200 photo-sized images without complaint, but past that, your browser may briefly hang while it allocates memory. If it does, just wait — it's not crashed, it's working.

RAM matters more than CPU. A 12-megapixel photo takes roughly 50 MB of RAM to decode. A batch of 100 such photos can momentarily peak at several gigabytes of memory. Closing other tabs helps if you hit the wall.

Mobile. Phones and tablets have less RAM and stricter background limits. Stick to smaller batches (10–20 images) on mobile devices.

ZIP downloads. Once your batch is converted, the "Download all as ZIP" button bundles every file into one archive — much faster than clicking 50 individual save links.

Frequently asked questions

Are there any limits?

No software-imposed cap. The only ceiling is what your browser and computer can handle. We suggest about 50 images at a time as a comfortable starting point — most modern laptops handle two or three times that without trouble.

Are my files uploaded to a server?

For supported image conversion flows, ConvertUnlimited does not provide a server-side upload endpoint. The browser reads and re-encodes selected image contents locally, then creates downloadable results in the tab. See how local processing works and how to verify it.

Will big batches slow my computer?

Briefly, yes. Each image decode and encode uses your CPU and RAM. Big batches (200+ high-resolution photos) can momentarily peak system memory. Use at your own discretion.

Why is it free?

The public site may use ads to support hosting and maintenance. The core tools are static browser utilities, so supported processing flows do not require a ConvertUnlimited upload service. Use the privacy build when you need the no-ads, no-analytics version.

What's the difference between WebP, JPEG, and PNG?

WebP is smallest at equivalent quality and supports transparency — best default for the web. JPEG is universal and best for photos when compatibility is the priority. PNG is lossless and supports transparency — best for screenshots, logos, and icons. The full breakdown is in our image format guide.

Does converting reduce image quality?

Lossy formats (WebP, JPEG) discard some information by design. At "High" or "Original" quality, the loss is invisible at normal viewing sizes. PNG is lossless — converting from PNG to PNG produces a bit-for-bit equivalent file.

Can I convert HEIC, RAW, or PDF files?

Not currently. The browser canvas API only decodes image formats the browser natively supports. iPhone HEIC photos can be exported as JPEG from Photos.app and then converted here; PDFs need a dedicated PDF tool.

Why is my converted file sometimes bigger than the original?

This happens occasionally when you convert from a more efficient format (for example, WebP) to a less efficient one (for example, PNG), or when you ask for "Original" quality on an already-compressed source. The tool always shows the before / after sizes so you can decide whether the conversion was worth it.

What browsers are supported?

All current browsers — Chrome, Edge, Firefox, Safari, and their mobile variants. There is no extension or plugin to install.

Is there a desktop app?

No, and we don't think there needs to be — the browser does everything an app would, with no install or update step. Just bookmark this page.

Privacy

Selected images. ConvertUnlimited converts images entirely inside your browser. Selected file contents are processed locally in your browser for this supported workflow. ConvertUnlimited does not provide a server-side upload endpoint for this processing flow. File contents are not intentionally uploaded by this tool.

Analytics. We use Google Analytics 4 to understand which features people use and how the site performs in aggregate. GA4 sets first-party cookies (typically named _ga and _ga_<property>) to count distinct visits, and Google truncates IP addresses before storage. The data we collect is page-level — what was loaded, from where, on what device — never the contents of files you convert. You can opt out by installing Google's Analytics Opt-out browser add-on, by enabling your browser's tracker-blocker, or by browsing in private/incognito mode.

Ads. We use Google AdSense to keep the tool free. Google and its ad partners may set additional cookies on the ad iframe to serve relevant ads and measure performance. You can manage personalised-ad settings at google.com/settings/ads, and European users can opt out of personalised advertising at youronlinechoices.eu.

Server logs. Your hosting provider's standard server logs (your IP address, browser type, referrer) are kept for normal abuse and security purposes only. They are not used for analytics or advertising.

Contact. For privacy questions, reach out via the project's GitHub.