filetity

BMP -> PNG · Local tool

BMP to PNG

Turn BMP files into PNG, which is much smaller and just as exact.

Last updated

  1. 01 / Your device

    the file stays here

  2. 02 / Browser memory

    the work runs locally

  3. 03 / Back to you

    saved on this device

When you would use this

Situations, not settings.

A bitmap you cannot afford to change
Diagrams, screenshots with text and anything going into a record need every pixel kept. PNG keeps them and still shrinks the file.
A folder of BMPs eating the disk
Nothing is given up in the move, so this is the safe conversion to run when you do not yet know what the files are for.
Output from legacy software going somewhere modern
Industrial, medical and till systems still write BMP. PNG is the format everything after them reads.

How it works / no cloud

A conversion engine, not an upload form.

Your browser decodes BMP, so filetity reads the bitmap and writes a PNG from the same pixels. Both formats keep every pixel exactly; the difference is that PNG packs them and BMP writes them out raw. Nothing is uploaded.

  • Offline ready
  • Installable app
  • No file limit queue

Straight answers

No accordion. Nothing hidden.

Is it free?
Yes, with no watermark and no page limit.
Does it need an account?
No. There is no account system.
Is my file processed on my device?
Yes. The file is read by your browser and never uploaded. There is no server to send it to.
What formats are supported?
BMP in. PNG out, one file per image, or a ZIP when you convert several.
What are the limits?
No image count limit. Very large bitmaps are bounded by the memory your browser will give a canvas. Nothing about the picture changes, so there is no setting here to get wrong.
Does it work on mobile?
Yes, on any modern mobile browser. Large files are limited by the memory the phone gives the browser.
Does it work offline?
Yes, after you have used it once. Your browser keeps what the tool needs, so it then works with no network connection.
Does this change the picture at all?
No. Both formats store every pixel exactly, so the PNG holds the values the BMP held. This is one of the few conversions with nothing to trade off.
Then why is the file so much smaller?
Because BMP does no compression and PNG does. The same pixels, packed properly. A screenshot or a diagram often drops by ninety percent or more; a noisy photograph drops by less, because there is less repetition to pack.
Can I get the BMP back?
Yes, pixel for pixel, in any editor that saves BMP. Nothing was discarded, so the round trip is exact. This page does not write BMP itself, because the encoder in your browser cannot.
Why does anything still use BMP?
Screen capture, scanner drivers, some medical and industrial software, and Windows programs old enough to predate PNG. It takes no library to write, which matters more in those places than file size does.
Can I shrink it while converting?
Yes. Pick a longest edge of 2048, 1600, 1024 or 640 and the bitmap is scaled down to fit, proportions kept, before it is written. Anything already smaller is left alone. Shrinking is the one step on this page that changes the picture, so leave it at original size if you want every pixel. The result line shows the size it produced.

Keep working locally

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