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Convert BMP to PNG free, without uploading
BMP to PNG shrank our 1281×1600 px test portrait from 5.87 MB to 4.46 MB (−24%). PNG is lossless, so nothing more is lost. Drop the BMP (.bmp, .dib) on the tool below and download the PNG; nothing is uploaded.
BMP to PNG
PNG · no file-size limit · original pixel size
No file-size limit is set: PixelFit saves at high quality and changes only the format and any pixel size you set.
Fit, background and padding white background
Saving presets is part of Pro.
The result appears here: the exact byte count, pixel size and quality, the size before and after, a preview and a download button.
The batch kit (one ZIP for up to 500 photos, several photos merged into one PDF) is part of Pro.
What changes from BMP to PNG
1 of these 2 points loses or alters something on the way from BMP to PNG; the rest carry over.
- Kept: Both formats are lossless here: every pixel of the BMP is stored exactly in the PNG.
- Lost or changed: Metadata is not carried over: the BMP's header resolution fields are dropped by the canvas.
Measured file size: BMP vs PNG
sharp 0.35.5 / libvips 8.18.7, 31 October 2026, long edge 1600 px; PNG saved as lossless, zlib level 6, RGBA, BMP as computed: 24-bit uncompressed.
| Sample | BMP | PNG | Change |
|---|---|---|---|
| portrait photo (1281×1600 px) | 5.87 MB (6,150,454 bytes) | 4.46 MB (4,679,548 bytes) | −24% |
| landscape photo (1600×1200 px) | 5.49 MB (5,760,054 bytes) | 4.74 MB (4,972,383 bytes) | −14% |
| scanned typed letter (1273×1600 px) | 5.83 MB (6,112,054 bytes) | 2.59 MB (2,714,410 bytes) | −56% |
| flat chart with a transparent background (1600×1000 px) | 4.58 MB (4,800,054 bytes) | 39.7 KB (40,653 bytes) | −99% |
What the numbers mean for BMP to PNG
Our portrait photo at 1281×1600 px: BMP 5.87 MB → PNG 4.46 MB (−24%, 1.3 times smaller).
Our landscape photo at 1600×1200 px: BMP 5.49 MB → PNG 4.74 MB (−14%, 1.2 times smaller).
Our scanned typed letter at 1273×1600 px: BMP 5.83 MB → PNG 2.59 MB (−56%, 2.3 times smaller).
Our flat chart with a transparent background at 1600×1000 px: BMP 4.58 MB → PNG 39.7 KB (−99%, 118.1 times smaller).
Per pixel, the portrait took 24.01 bits as BMP and 18.27 bits as PNG, a difference of 1.4 MB on 2,049,600 pixels.
Per pixel, the chart took 24.00 bits as BMP and 0.20 bits as PNG, a difference of 4.54 MB on 1,600,000 pixels.
PNG came out smaller than BMP on all 4 samples, from −14% to −99%.
Reducing the portrait PNG to 256 colours brought it down to 782 KB (made from the original photo), still 3.1 times a quality 85 JPG, and a 256-colour palette can band smooth skin and sky tones.
How to convert BMP to PNG
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Add the BMP file
Drop the .bmp, .dib file on the tool at the top of this page, tap to choose it, or paste it.
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Keep PNG selected
PNG is pre-selected and saved in full colour. Type a maximum size in KB only if the destination sets one; PixelFit then tries fewer colours (a palette PNG) and, if that is not enough, fewer pixels. Our BMP test portrait came out at 4.46 MB as PNG with no limit set.
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Download the PNG
Save the file ending in .png; its size in KB shows before you save.
BMP and PNG side by side
BMP (1990) next to PNG (1996); browser figures checked 31 October 2026.
| Property | BMP | PNG |
|---|---|---|
| File extensions | .bmp, .dib | .png |
| MIME type | image/bmp | image/png |
| Compression | lossless | lossless |
| Transparency | no | yes |
| Animation | no | yes |
| Largest size | 32,767 px per side | 2,147,483,647 px per side |
| Colour depth | 1 to 32 bits per pixel | 1 to 16 bits per channel |
| Metadata | header resolution fields | text chunks, eXIf and ICC data |
| First published | 1990 | 1996 |
| Opens in | Chrome, Edge, Firefox, Safari (every current browser) | Chrome, Edge, Firefox, Safari (every current browser); about 97.49% of browsers in use |
| Good for | old Windows programs and scanners that need raw pixels | screenshots, logos, signatures on white and images with transparency |
| Weak for | anything you upload or e-mail, because pixels are usually stored uncompressed | large photos, which come out several times bigger than a JPEG |
| Specification | Bitmap Storage (Microsoft Win32 documentation) | Portable Network Graphics (PNG) Specification, Third Edition (W3C) |
When not to change BMP to PNG
- Keep the original BMP if a program or archive needs it; the PNG is for sending and uploading.
- If the destination already accepts BMP, upload the original: every change of format re-encodes the pixels.
Browser support for BMP and PNG (October 2026)
Reading BMP (.bmp, .dib): Chrome, Edge, Firefox, Safari (every current browser).
Writing PNG from that BMP: Chrome 50+, Edge 79+, Firefox 18+, Safari 11+ (MDN compatibility data for canvas.toBlob, checked 31 October 2026).
Upload forms that ask for PNG
10 of the 61 application portals we checked accept PNG photos, 1 of them with a limit of 50 KB or less. A few of them, for this BMP file (verify with the official notice before you upload):
- Japan eVISA: PNG photo, up to 2 MB (also takes JPG, GIF, BMP, HEIC).
- Oman eVisa: PNG photo, up to 512 KB (also takes JPG, PDF).
- Singapore ABTC: PNG photo, up to 8 MB, 400 × 514 px (also takes JPG, HEIC).
- Indonesia e-VOA: PNG photo, up to 200 KB (also takes JPG).
Where BMP files come from
BMP files usually come from old Windows programs, Paint, scanners or screenshots tools that store raw pixels. Because the pixels are uncompressed, a BMP photo is several megabytes, far above typical upload limits, and changing it to PNG fixes that.
Sources
- Bitmap Storage (Microsoft Win32 documentation), Microsoft Learn, checked 31 October 2026: learn.microsoft.com/en-us/windows/win32/gdi/bitmap-storage
- Portable Network Graphics (PNG) Specification, Third Edition (W3C), W3C, checked 31 October 2026: w3.org/TR/png-3/
- MDN Web Docs, Image file type and format guide (which browsers decode BMP), checked 31 October 2026: developer.mozilla.org/en-US/docs/Web/Media/Guides/Formats…
- MDN browser-compat-data, HTMLCanvasElement.toBlob (which browsers write PNG), CC0, checked 31 October 2026: github.com/mdn/browser-compat-data/blob/main/api/HTMLCanv…
- Test photo “President Barack Obama.jpg” by Pete Souza (Official White House photo), public domain, measured by PixelFit with sharp 0.35.5 / libvips 8.18.7 on 31 October 2026: commons.wikimedia.org/wiki/File:President_Barack_Obama.jpg
Frequently asked questions
Can I convert BMP to PNG for free?
Yes. The BMP to PNG change runs free on your device, with no sign-up and no upload, one file or up to 25 at a time; Pro raises the batch to 500 with one ZIP download.
How do I convert BMP to PNG?
Drop the BMP on the tool above, keep PNG selected, and download the .png file. Add a KB limit if the destination has one.
Does converting BMP to PNG reduce quality?
Both formats are lossless here: every pixel of the BMP is stored exactly in the PNG. In our test a 1281×1600 px portrait went from 5.87 MB as BMP to 4.46 MB as PNG (−24%).
Why convert BMP to PNG?
PNG suits screenshots, logos, signatures on white and images with transparency; BMP is a poor fit for anything you upload or e-mail, because pixels are usually stored uncompressed.
Related
More BMP format changes
- BMP to JPG same BMP input
- BMP to PDF same BMP input
Other files to PNG
- ICO to PNG also ends as PNG
- GIF to PNG also ends as PNG
- JFIF to PNG also ends as PNG
- JPG to PNG also ends as PNG
- AVIF to PNG also ends as PNG