It depends on the service, and you usually cannot check. Most online converters upload your file, convert it on their server and keep a copy for a set time. Read each service’s own retention statement below, then test a converter that never sends your file.
What happens after you click upload
You send your file to a server you do not control. The server converts it, stores the result for you to download, and deletes both after a retention window that the service sets. In between, you rely on the service to:
- keep no copy beyond the window it states
- not analyse the file or train models on it
- not share it with third parties
- actually delete it when it says so
None of this is visible from your side. The file left your device the moment you clicked upload.
How long each service keeps your file
These are the statements from the services’ own pages.
| Service | How long it keeps your file, quoted | Source |
|---|---|---|
| CloudConvert | “automatically at the latest after 24 hours” | cloudconvert.com/privacy |
| Zamzar | “Free converted files are stored securely for a maximum of 24 hours” | www.zamzar.com |
| FreeConvert | “automatically delete them after 8 hours” | www.freeconvert.com |
| ezgif (upload mode) | “All uploaded files are automatically deleted 1 hour after upload.” | ezgif.com/webp-to-png |
Quotes are copied from each service’s own pages. Limits change, so check the source before you rely on one. Checked on 2026-10-31.
What security sources advise
- Experian: “When you submit a file to a conversion website, there’s no way to know whether it’ll be stored or deleted.” (Experian, 29 May 2025)
- Kaspersky: “For sensitive or confidential files, consider using offline or local software instead of online services.” (Kaspersky, 25 February 2025)
- Intego: “There are many potential security and privacy concerns surrounding file converter sites.” (Intego)
Contracts, IDs, medical records and client files are the files to keep off any server. The FBI has also warned about fake converter sites that return files carrying malware.
Test any converter yourself
- Open the converter page, then open your browser’s developer tools (F12, or Ctrl+Shift+I on Windows and Linux, Cmd+Option+I on Mac).
- Click the Network tab and clear the list.
- Convert a file.
- Look at the requests. A converter that uploads shows a request that carries your file, and its size is about the size of your file.
On WebConverter you will see requests for page assets and small analytics calls. None of them carries your file. Our automated tests check this: they convert a file with a unique marker inside and fail if the marker appears in any request.
Convert without uploading
WebConverter runs the conversion inside your browser, so there is no server copy to delete. Start with Convert Anything, or go straight to images, audio, video to MP3, PDFs or documents. For a category comparison see WebConverter vs cloud converters.
Convert with the internet off
After you open a tool once, images and audio convert with the network switched off. Offline file converter shows which tools we have tested and how to install the app.
Frequently asked questions
Is CloudConvert safe?
CloudConvert’s privacy page says files are deleted “automatically at the latest after 24 hours” and that it is bound by the GDPR. That is the service’s own statement, and we pass no verdict on it. With WebConverter nothing is uploaded, so there is no retention window to trust. See WebConverter vs CloudConvert.
Is Zamzar safe?
Zamzar’s page says “Free converted files are stored securely for a maximum of 24 hours”. That is the service’s own statement. With WebConverter nothing is uploaded. See WebConverter vs Zamzar.
Are online file converters safe in general?
Some are run by established companies with published policies, others are not. You cannot verify what happens to a file after you upload it, so keep sensitive files on your device and use a converter that runs locally.
Does WebConverter see my files?
No. The conversion runs in your browser and your file is never sent to our servers. The site is supported by ads and uses analytics, like many free sites, and neither of them receives your file.
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