Is BMP image checker
Find out whether a file is truly a BMP, 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 BMP 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.
The uncompressed legacy format
BMP is Windows' classic uncompressed bitmap: simple, widely readable, but often enormous compared with PNG or JPEG. Files with a .bmp extension are not always genuine bitmaps, since conversions and renames over the years leave misleading names behind.
This checker reads the two-letter BM signature and header of each file instead of trusting the name. That confirms whether you really have a BMP before you commit to its large file size or convert it away.
On-device checks, zero uploads
Each file is examined where it already is — inside your browser on your phone or computer — by reading only its first bytes. No server ever receives your images, which makes the tool safe for screenshots containing personal data, legacy archives and work documents.
Just open the page, add up to ten files, and read the verdicts instantly with no account or queue. When you close the tab, nothing of your files remains behind except the cached app shell.
When to check for BMP and what to do next
Verify BMP before importing into old software, games or embedded systems that demand genuine bitmaps, or before converting a bulky archive to modern formats. The detected-format column exposes JPEGs and PNGs masquerading as BMP at a glance.
Real BMPs usually deserve conversion to PNG or WebP to shrink them dramatically without visible change. Use our image converter for that, or run Analyze image to see exactly how heavy each file is.
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 are BMP files so large?
BMP stores pixels almost uncompressed, typically three bytes per pixel plus a small header. A photo that is 2 MB as JPEG can easily exceed 20 MB as BMP.
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 BMP, PNG or JPG and check again.
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