Is WebP image checker
Find out whether a file is truly a WebP, whatever its extension claims. Everything is checked on your device.
- Your files are never uploaded
- Processed on your device
- Works offline
- Free, no sign-up
Drop your images here
Images · up to 10 files, 100 MB each
or paste with Ctrl+VLive preview
Settings
No settings needed. Add your files and convert.
Nothing is uploadedHow it works
Add your images
Choose one or more image files to check for the WebP format.
Read the verdict
See the detected format and a clear Yes or No answer for each file.
Act on the result
Convert or rename with confidence, knowing the true format of every file.
Why WebP detection is tricky
WebP files downloaded from the web are frequently saved with .jpg or .png extensions by browsers and messaging apps, which then confuses editors, upload forms and older software. The extension tells you nothing reliable; only the file's internal signature reveals the truth.
This checker reads those signature bytes for every file you add, so a WebP hiding as a JPEG is exposed instantly. That saves you from failed uploads and from converting files that are already in the format you wanted.
Privacy built in, not bolted on
From the first byte to the final verdict, everything happens locally in your browser on your own device. No copies are made on any server, no analytics sees your pictures, and closing the tab leaves no trace of the files you inspected.
You never create an account or join a queue: just open the tool, check up to ten images at once, and get on with your day. The app shell may be cached for offline use, but your images never are.
When to check for WebP and what to do next
Use this before publishing to a site that requires WebP, before converting a batch to save bandwidth, or when an image behaves oddly in an editor. WebP supports both transparency and animation, so confirming the format helps you pick the right next conversion step.
If a file is not WebP yet, our image converter can make it one properly. To see dimensions, weight and dominant colours as well, follow up with Analyze image.
Questions
Are my files uploaded?
No. The signature check runs inside your browser on your own device. Your files are never sent to us or to anyone else.
Is it free?
Yes. Free to use, with no sign-up, no watermark and no daily limits.
Why do my JPG files turn out to be WebP?
Many websites serve WebP images even when the link or download says .jpg. Browsers save exactly what they received, so the extension is misleading and the contents are genuinely WebP.
What if the format shows as unknown?
The file is likely damaged, truncated, or in a format browsers cannot recognise. Re-export it from the original app as PNG, JPG or WebP and check again.
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