Aisha K.
Mar 12, 2026
Clean layout and the results update instantly. Exactly what I needed for a quick planning check.
Image Converters
BMP to PNG Converter (PNG to 24-bit BMP)
Instant private convert
Modernize BMP files to PNG or export PNG to 24-bit BMP for legacy apps—privately in the browser.
Files never leave your browser
Conversion runs on this device. CalculioHub does not receive uploads of your documents, photos, or media. No account required.
- Your files
- Stay in memory / local processing — not sent to our servers.
- Canvas (on-device)
- No CDN engine download for conversion — your image bytes stay local.
Recent job names below are stored locally as text only — never the file bytes.
Direction
Files never leave your browser. Batch up to 20 images.
Drop BMP images, or browse
BMP → PNG · up to 20 files · max 25.0 MB each · private
Browse filesSize budget0 B / 25.0 MB
Output options
Email = smaller & shareable · Print = high quality · Archive = near-lossless original size
Source dimensions appear after a previewable file loads.
Drop images to preview
Converted preview appears here
Plain-English guide
Terms & how it works
Confused by a field? Read the short definitions here while you use the tool.
- pixels
RGBA buffer
Canvas ImageData used for BMP packing.
- rowSize
Stride
BMP rows padded to 4-byte boundaries.
- bg
Background
Fill used when flattening transparency for BMP.
When to use this BMP ↔ PNG
Common use cases
- Convert phone photos for email or web upload limits
- Switch formats for design handoff without installing apps
- Batch-friendly one-off conversions in the browser
Localized examples
- iPhone HEIC photo workflows
- WebP and PNG web asset preparation
What you get
- Runs in your browser — nothing uploaded by default
- Common photo and icon formats supported
- Free online converter, no watermark
How to Convert BMP ↔ PNG Step-by-Step
- 1Select BMP → PNG or PNG → BMP.
- 2Drop an image and optionally resize.
- 3For PNG → BMP, pick a background fill for transparency.
- 4Preview both sides, then download.
- 5Clear when switching files.
Governing formula
PNG ⇄ BMP24(Canvas pixels)
BMP is decoded to a bitmap, redrawn at the target size, then either PNG-encoded via toBlob or packed into a BITMAPINFOHEADER BMP.
Use the defaults, then adjust one input at a time to see the result update instantly—no sign up.
Variable definitions
- pixels
RGBA buffer
Canvas ImageData used for BMP packing.
- rowSize
Stride
BMP rows padded to 4-byte boundaries.
- bg
Background
Fill used when flattening transparency for BMP.
- 24-bit BMP export only.
- Everything runs locally.
Frequently Asked Questions
Uncompressed 24-bit Windows BMP. Alpha is flattened onto the background color.
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Community
Reviews & Ratings
See what others think about this tool, then leave your own rating to help improve CalculioHub.
4.8
out of 5.0
4 reviews
Daniel R.
Feb 28, 2026
Very usable on mobile. Would love a save/export option later, but the math feels solid.
Priya S.
Feb 3, 2026
The FAQ section answered my questions before I even had to search. Smooth dark mode too.
Marcus L.
Jan 19, 2026
Simple inputs, clear outputs. This replaced three bookmarks I used to juggle.
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