BMP to PNG Converter: Free, Private, No Upload

Convert BMP files to PNG in your browser. Lossless output, batch up to 20 files at once, no upload, no account, no watermark. Your files never leave your device.

BMP to PNG
Batch up to 20 files
No upload, no account
Metadata stripped

1Add up to 20 images
2Pick from 18 formats
3Download or copy the code

Processed on your device. Your images are never uploaded, and metadata is stripped. How we keep it private

How do I convert BMP to PNG for free?

Drop your BMP files into the tool above, choose PNG as output, and download the result. Everything runs in your browser, so nothing is uploaded and there is no limit or watermark. It works on Windows, Mac, Linux, ChromeOS, iOS and Android — anywhere you have a modern browser.

Price: Free, no credits and no daily cap
Account required: No
File uploaded to server: No, processed locally in your browser
Batch limit: Up to 20 files at once
Input format: BMP
Output format: PNG
Best for: PNG workflows, lossless quality, editing, printing
Works on: Chrome, Edge, Firefox, Safari, iOS and Android browsers
Privacy: No upload, no tracking, metadata stripped
Output quality: Lossless, exact pixels

How to convert BMP to PNG

1
Drop your BMP files
Drag up to 20 BMP files onto the page or click to choose them. Everything runs in your browser.
2
PNG is preselected
Output is already set to PNG. Adjust quality, resize or batch if you want.
3
Download
Save each PNG, or download all of them together as a ZIP.

BMP to PNG: what changes and when it makes sense

BMP is a Bitmap image format. It is best known for a simple structure that legacy programs and embedded systems can read without a decoder library. The main drawbacks are enormous files and no reliable transparency.

PNG is a Portable Network Graphics format. It is best known for exact pixel reproduction, crisp text and edges, and full alpha transparency. The main drawbacks are large files for photographs and no lossy mode for trading quality against size.

BMP vs PNG at a glance

Property	BMP	PNG
Type	Raster image	Raster image
Compression	Usually uncompressed (run-length encoding exists but is rare)	Lossless (DEFLATE), with an optional 8-bit palette mode
Transparency	None	Full alpha channel with soft edges
Animation	No	No
Colour depth	1 to 32 bits per pixel	8 or 16 bits per channel, or 8-bit indexed colour
Support	Opens in browsers and most desktop software, but almost never used on the web	Opens in every browser and image editor
History	Created by Microsoft for Windows 1.0 in 1985 as the native bitmap format for the Windows Graphics Device Interface. The "BM" signature has been unchanged since then. Still used in embedded systems and legacy Windows software.	Created in 1995 as a free, patent-unencumbered replacement for GIF after Unisys began charging royalties for LZW compression. Became a W3C Recommendation in 2003. The signature bytes are 89 50 4E 47 0D 0A 1A 0A — "PNG" with newlines designed to catch file corruption.

What actually changes in this conversion

Both BMP and PNG are lossless, so the pixels come through unchanged.
BMP has no alpha channel, so every pixel is already opaque.
Expect the PNG file to be far smaller than the BMP source.
EXIF, GPS and camera data are stripped on every conversion. That is good for privacy, but you lose capture dates.

About BMP: history and technical details

Created by Microsoft for Windows 1.0 in 1985 as the native bitmap format for the Windows Graphics Device Interface. The "BM" signature has been unchanged since then. Still used in embedded systems and legacy Windows software.

Technical: File header 14 bytes (signature, size, reserved, offset) followed by DIB header (40+ bytes). Supports 1, 4, 8, 16, 24, 32-bit pixels. Rows padded to 4-byte boundaries. Pixels can be stored bottom-up or top-down. Optional RLE4/RLE8 rarely used.

Real-world size: A 12-megapixel photo is 36 MB as 24-bit BMP. As JPG it is 2-4 MB (90% smaller). A 1920x1080 screen at 32-bit BMP is 8.3 MB; as PNG 200-600 KB.

Popular tools: Windows Paint, IrfanView, XnView, ImageMagick, GIMP, Adobe Photoshop, embedded dev tools.

Alternatives: PNG (lossless, 5-20x smaller), TGA (game pipelines), TIFF (professional print), JPG (lossy, much smaller).

About PNG: what you get

Created in 1995 as a free, patent-unencumbered replacement for GIF after Unisys began charging royalties for LZW compression. Became a W3C Recommendation in 2003. The signature bytes are 89 50 4E 47 0D 0A 1A 0A — "PNG" with newlines designed to catch file corruption.

Technical: Uses DEFLATE (LZ77 + Huffman) compression. Two main modes: 8/16-bit truecolour with alpha, and 8-bit indexed with up to 256 colours. Filters per scanline (None, Sub, Up, Average, Paeth) before DEFLATE for better ratios.

Real-world size: A 1920x1080 screenshot is 200-600 KB as PNG. As JPG at quality 85 it is 100-300 KB but with blurry text. A 12-MP photo is 18-25 MB as PNG, 2-4 MB as JPG. PNG wins on text, JPG wins on photos.

Popular tools: Adobe Photoshop, GIMP, Figma, Sketch, Snipping Tool, macOS Screenshot, ImageMagick, pngquant, oxipng.

Alternatives: WebP lossless (20-30% smaller), AVIF (better for photos), JPG (photos only), SVG (vector graphics).

Browser and software compatibility

BMP: Opens in browsers and most desktop software, but almost never used on the web. PNG: Opens in every browser and image editor.

PNG output opens in virtually every browser, operating system and editor.

Why people move away from BMP

A 12 megapixel photo saved as 24-bit BMP is roughly 36 MB because pixels are stored almost raw.
BMP has no practical support for transparency, and almost no web workflow expects it.

Why people choose PNG

PNG keeps every pixel, making it safe for screenshots, diagrams, logos and anything with text.
It stores full alpha transparency, including soft shadows and anti-aliased edges.
Lossless output means you can keep editing without generational loss.

Common mistakes with BMP

Using BMP on web pages — files are 10-20x larger than PNG with zero benefit
Expecting BMP transparency to work — most viewers ignore the alpha channel
Converting large BMPs without checking disk space — can fill your drive

Best practices for keeping quality

BMP is raw pixels, so the source has no compression damage. Convert at full size and choose the output quality freely.
Converting a lossy file to PNG stops further loss but does not restore detail already discarded. Expect a much larger file with no visible gain.
PNG suits screenshots and flat graphics. For photographs, a lossy format is usually the better trade.
Resize before converting if the image will be shown small. A 4000 pixel photo displayed at 800 pixels wastes bytes in any format.
Check the result at 100 percent zoom, especially around text, edges and gradients, before you replace any originals.
Keep your original files. Conversions to a lossy format cannot be undone.
When you convert a set of images, use the same quality setting for the whole batch. The converter handles up to 20 files at once.

BMP to PNG questions

Quick answers about privacy, quality, supported formats, file limits and how PNG works.

Why convert BMP to PNG?

PNG is lossless. It keeps every pixel exactly. It is the safe choice when you plan to edit, print or need exact pixel data.

Will converting BMP to PNG lose quality?

No. PNG is lossless, so nothing is thrown away.

Does PNG keep transparency?

Yes. PNG supports full transparency, so transparent areas in your original are kept.

Are my files uploaded?

Never. Everything runs in your browser. Your files never leave your device. Open DevTools Network tab while processing — you will see no upload request.

Can I convert many files at once?

Yes, up to 20 files at once. Download them individually or all together as a ZIP.

Does the converter strip metadata?

Yes. Browsers do not pass EXIF data through a canvas, so GPS, camera model and dates are removed on every conversion. That is good for privacy.

Is it free?

Yes. No credits, no daily cap, no account, no watermark. The practical limit is your device memory.

Is PNG lossless?

Yes. PNG uses DEFLATE compression, which is fully lossless. Every pixel is preserved exactly. PNG can reduce file size but never changes any pixel value.

Can PNG be animated?

Standard PNG is not animated, but APNG (Animated PNG) exists and is supported by most modern browsers. It is rarely used because WebP and GIF animation are better supported.

Why are PNG files so large?

Because PNG preserves every pixel with no lossy compression. Photographs have millions of slightly different pixel values that DEFLATE cannot compress well. This is why PNG of photos can be 10x larger than JPG.

Your files never leave your device

No upload, no account, no tracking. Everything happens in your browser using the Canvas API and WebAssembly. You can confirm this in your browser's DevTools Network tab while the tool runs — no request carries your file. See why ToolDeck is different.