BMP to PNG converter
Convert BMP images to PNG in your browser.
Processed in your browser. This file is converted on your device and is never uploaded.
Converter
.bmp, .dib up to 50 MB. You can also drag a file here.
No file selected.
About this tool
BMP turns up in output from older Windows software, scanners, and some scientific instruments. PNG stores every pixel exactly and keeps transparency, which makes it the safe choice for graphics, screenshots, and anything with sharp edges or text.
This tool converts BMP to PNG entirely in your browser. The image is decoded, drawn, and re-encoded on your device, so nothing is uploaded and the size of the file costs you no waiting.
Supported formats and limits
- Input
- .bmp, .dib
- Output
- .png (image/png)
- Output name
- The original name with the new extension, for example photo.bmp becomes photo.png.
- File size limit
- 50 MB
- Processing
- In your browser. The file is not uploaded.
BMP against PNG
| Feature | BMP | PNG |
|---|---|---|
| Compression | None, stored as written | Lossless |
| Colour | 8 bits per channel | 8 bits per channel |
| Transparency | None | Full alpha channel |
| Animation | No | No |
| Keeps EXIF | No | Yes |
| Browser support | Every browser since 1995 | Every browser since 1997 |
| Size of a photograph | 8 to 20 times a JPG | 3 to 5 times a JPG |
| Published | 1990 | 1996 |
When you would want this
You need the background to stay transparent
PNG carries a full alpha channel and BMP does not carry a usable one, so this is the conversion that lets a logo or a cut-out sit on any background without a white box around it. Anything you are going to place over a coloured surface, a photograph, or a gradient wants to be in a format that can say a pixel is only partly there.
The file has to be smaller
A photograph as PNG is roughly 3 to 5 times the size of the same picture as JPG, against 8 to 20 for BMP. On a page that matters twice: less to download, and a faster largest-contentful-paint, which is one of the things a search engine measures. For an email attachment or an upload limit it just matters once.
How to use it
- Choose a .bmp / .dib file, or drag one onto the page.
- Optionally set a width or height to resize at the same time.
- Select Convert, then download the PNG file.
Limitations
- PNG is lossless, so a photograph saved as PNG is typically several times larger than the same photograph as JPEG or WebP.
- Metadata is not preserved. EXIF fields, including camera settings and GPS location, are dropped, which is a privacy benefit but worth knowing if you rely on them.
- Colour profiles are not preserved, so an image in a wide-gamut profile may shift slightly.
- The camera's EXIF orientation is applied, so a photo taken sideways comes out upright rather than rotated.
Other ways to do this
The program already on your computer
Preview on macOS, Photos on Windows, GIMP, Photoshop will open a BMP and save it as PNG, and if you have one of them installed and only one file to convert, that is a perfectly good answer. It stays on your machine the same way this does. Where it stops being convenient is a folder of forty files, or a machine you do not own.
ImageMagick, from a terminal
One command converts a directory: magick mogrify -format PNG *.BMP. If you already have it installed this is the fastest way to do a hundred files, and it scripts. It is also a dependency to install and a syntax to learn, which is a poor trade for converting one image once.
An online converter that uploads
Most sites offering this send your file to a server, convert it there, and give you a link back. They can do formats a browser cannot, which is a real advantage. The cost is that your file was on somebody else's machine, governed by a retention policy you did not read. That is the whole difference here: this page converts BMP to PNG using code your browser already downloaded, so there is no server holding it afterwards.
Frequently asked questions
- Is my image uploaded?
- No. The conversion runs entirely in your browser. The image never leaves your device and no request carrying it is made.
- Does converting to PNG lose any quality?
- The conversion itself does not. PNG is lossless, so every pixel it is handed is written exactly as it arrived and nothing is discarded on the way. What it cannot do is recover detail your BMP had already lost before it got here: a lossless format preserves what it is given, it does not restore what is gone.
- Will the PNG be bigger or smaller than the BMP?
- Smaller or larger depending on the pair, and here the arithmetic is public: a photograph as BMP runs 8 to 20 times the size of the same picture as JPG, and as PNG it runs 3 to 5. The comparison table above states both, so you can tell before converting rather than after.
- Why is my BMP file so enormous?
- Because BMP barely compresses: it stores each pixel more or less as written, so the size is width times height times bytes per pixel and almost nothing else. That is why it opens instantly and why it is impractical to send. Converting to PNG is the usual fix, and the size drops by a large multiple.
- Can I resize while converting?
- Yes. Set a width, a height, or both. With proportions kept, one dimension is derived from the other, and giving both fits the image inside that box rather than distorting it.
- Do I need to install anything or create an account to use BMP to PNG converter?
- No, to all of it. BMP to PNG converter runs inside the browser you already have, with no sign-up, no download, no watermark on the result, and no cap on how many files you convert. There is nothing to uninstall afterwards either, because nothing was installed.
- Does BMP to PNG converter work offline?
- Once the page has loaded, yes. The conversion runs on your device, so it needs no connection to do the work. The first visit fetches the page and the code that does the converting; after that a lost connection stops nothing, and a converted file appears exactly as it would online.
- How large a file can BMP to PNG converter handle?
- The limit is 50 MB. It is a deliberate one rather than a technical ceiling: the real constraint is memory, and a file that decodes to more than the device can hold fails in a way that is hard to explain. Phones run out well before laptops do, which is why the limit is set where it is.
- Can I convert several files at once with BMP to PNG converter?
- Not here: this tool takes one file at a time, because what it does depends on choices you make about that particular file. Convert them one after another, or look at the batch converters in the same category, which are built for a folder at a time.