BMP to JPG
Convert supported BMP bitmaps to JPG locally, control quality and background, and download a batch ZIP.
This tool runs entirely in your browser. Your data is never uploaded, never stored, and never leaves your device.
BMP to JPG converts supported bitmap photos into JPEG with controlled quality, proportional resizing and a chosen background for explicit alpha.
How to use it
- 1Choose supported uncompressed or bitfields BMP files.
- 2Set JPEG quality and maximum edge; choose a background if the BMP has an explicit alpha mask.
- 3Convert, review actual image size and appearance, then download JPG files individually or together in a ZIP.
Example
- Input
- 1,600 × 800 BMP; maximum edge 640
- Output
- 640 × 320 JPG
The output is resized and encoded with lossy JPEG compression.
What happens to your data
A bounded local BMP decoder reads the source pixels in this browser. No bitmap file is uploaded for decoding, JPEG conversion or archive creation.
Last updated October 2026
Turn an uncompressed Windows bitmap into a JPG for email, a document or a photo uploader. Choose JPEG quality, reduce the maximum edge if needed, and check the exported size before saving. Multiple bitmaps can be converted into separate named files and packaged in one ZIP, without sending them to a server.
BMP is often used for older screenshots, scans and application exports. JPEG is usually a better fit for photographic content; sharp diagrams and text may look better as PNG. JPEG is lossy, so keep the original bitmap when you need to retain every source pixel or use BMP to PNG for a lossless output encoding.
How it works
A bounded local decoder reads the bitmap header, dimensions, row padding, palette and color masks before allocating the output raster. It supports uncompressed 1-, 4- and 8-bit palette images; 16-, 24- and 32-bit images; and 16/32-bit bitfields with valid non-overlapping contiguous masks. Bottom-up and top-down rows are handled explicitly. RLE, embedded JPEG/PNG compression and calibrated or embedded color-profile BMP files require re-export first.
Every source must be a complete BMP no larger than 10 MiB, 12 million pixels or 8,192 pixels per side. The batch accepts up to 20 files and 50 MiB combined. A renamed PNG, truncated row, invalid palette index or overlapping mask is reported as an error rather than producing a misleading successful file. Conventional 32-bit BMP without an explicit alpha mask is opaque; unused padding bytes are not interpreted as transparency.
JPEG removes transparency, so an explicit BMP alpha channel is composited over the selected background. Quality 1–100 controls the browser's JPEG encoding, and 100 is still lossy. Maximum edge reduces dimensions without cropping or enlarging. This can save more space than merely changing format, but it also changes the pixel data.
The preview and byte comparison describe the actual result rather than promising a size reduction. Original bitmap metadata and color profiles are not copied. Results run sequentially and are limited to 60 MiB total; failed files are excluded from a ZIP and duplicate filenames are numbered. Changing the source or an option clears old exports, and Cancel discards the pending conversion.
Worked example: Resize an application bitmap for an attachment
- Input
- 1,600 × 800 uncompressed BMP; maximum edge 640
- Result
- 640 × 320 JPG
The bitmap is resized proportionally and encoded as a lossy JPEG.
Common use cases
- Making a bitmap scan compatible with a JPEG-only upload form
- Reducing dimensions of older photographic BMP exports
- Preparing a folder of bitmaps as individual email-ready images
- Selecting the background for a bitmap with explicit alpha
Frequently asked questions
Should I convert a BMP screenshot to JPG or PNG?＋
PNG is usually preferable for crisp text, line art and screenshots because JPEG can add artifacts around edges. JPEG is useful when photographic content or a JPEG-only destination is the priority. Review the downloaded file at its intended display size.
Does BMP to JPG always make a smaller file?＋
No. Many uncompressed photographic bitmaps become smaller, but the output depends on dimensions, content and JPEG quality. The tool reports actual input and output bytes so you can decide.
Which BMP variants are supported?＋
Uncompressed palette BMP at 1/4/8 bits, uncompressed 16/24/32-bit BMP, and valid 16/32-bit bitfields are supported. RLE, embedded JPEG/PNG and calibrated or embedded color-profile variants are rejected with a re-export instruction.
What happens to 32-bit BMP transparency?＋
Only an explicit valid alpha mask is treated as alpha. Ordinary 32-bit BMP without that mask is opaque. For JPEG, supported alpha is flattened onto your chosen background.
Can I fix a broken BMP by renaming it?＋
No. The converter checks actual BMP bytes and row boundaries. A misleading extension or truncated file needs a valid re-export from the source application.
Does the tool upload my bitmap files?＋
No. BMP parsing, pixel decoding, resizing, JPEG encoding and ZIP assembly all run in this browser. Download the results before leaving the page.
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