How UltConvert works

Before anything is uploaded

Each tool page opens with the settings for its job already filled in: the page for a 50 KB photo starts at 50 KB, a format page starts with its target format. You can change the core options next to the file list or open the advanced settings for finer control.

While you choose files, everything happens on your device. The page rejects a file with the wrong extension, one over the size cap or a batch with too many files before a single byte is sent, and it builds thumbnails and PDF page previews in the browser so you can pick pages, crop or reorder without uploading. If you close the tab at this point, nothing has left your computer.

On our servers

Pressing the convert button starts the only network step. Your files are sent over an encrypted HTTPS connection to the processing service at api.ultconvert.com, and a short automated check may run first to keep bots from flooding the queue. Each job is handled by a worker that runs established open-source engines for images, PDFs, documents, audio and video with the options you chose, and the page shows its progress until the result is ready.

Workers only read a file to carry out the job. Nobody at UltConvert opens it, its name and content are not logged, and it is not used for anything else, including training AI models. The Privacy Policy lists exactly which technical data is recorded.

Download and deletion

Results appear on the same page with their new size, and for images their dimensions, so you can compare them with the original before saving. You can download each file on its own or the whole batch as a ZIP archive.

Deletion is automatic and happens in two stages. The uploaded original is removed as soon as the output has been produced. The output itself is kept for 30 minutes so you have time to download it, then deleted together with its link. After that the file cannot be recovered, by you or by us, so save what you need straight away.

What runs in your browser and what runs on our servers

Pages for browser-based tools say so next to the tool, and their results appear as you type.

Limits

Most file tools accept up to 20 files per batch and up to 95 MB per file. A few tools use different numbers because of the way they work: merging and archiving need many inputs, while trimming and splitting produce many outputs from each file.

The limits are shown on every tool page and are checked in your browser before upload, so an oversized batch is caught immediately instead of failing halfway.

Formats and tools

Across its 370+ tools, UltConvert reads more than 210 file formats, from everyday JPG, PNG, HEIC, PDF, DOCX and MP4 to camera RAW files, e-books, fonts, subtitles, archives, CAD drawings and 3D models. Each converter page lists the formats it accepts, and the format pages explain what changes when you move from one format to another.

Tools are grouped into 6 categories. Pick one to see every tool in it:

• ImageConvert, compress and resize images.
• PDFCompress, merge, split and convert PDFs.
• Documents & DataConvert documents, ebooks and data files, and extract text with OCR.
• VideoConvert, compress and trim videos, or turn them into GIFs.
• AudioConvert, trim, compress and transcribe audio files.
• More toolsTools for ZIP, fonts, subtitles, QR codes, CAD and 3D.

Security in practice

• Every page and every transfer uses HTTPS.
• Uploads are stored apart from the website and reachable only through an expiring link.
• Files are never copied to backups and never published.
• There are no accounts, so there are no passwords or file histories to leak.
• Requests are rate-limited and checked for abuse to keep the service available for everyone.

When a job does not work

If a file cannot be processed, the page tells you why: an unsupported or damaged file, a password-protected document, a file over the size cap, or a busy moment on the servers. Where another tool fits the file better, the error message links to it. For anything else, contact us with the page address, the file type and size, and what you saw.