BMP to JPG
Turn large BMP bitmaps into compact JPG images that are easy to email, upload and share. Add one file or a whole folder, set the quality, compare the file sizes and download each JPG or a ZIP. Everything happens in your browser, nothing is uploaded.
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Only used by 32-bit bitmaps with alpha.
How to use the BMP to JPG
- Add your BMP files by dropping them into the box or clicking Choose BMP files. You can add many at once.
- Set the quality. 85 to 92 looks identical to the original for most images and gives much smaller files.
- Optionally resize or pick a background color for bitmaps with transparent areas.
- Compare the sizes shown on every card. Changing a setting re-converts all files instantly.
- Download each JPG or press Download all as ZIP.
BMP vs JPG at a glance
| BMP (bitmap) | JPG / JPEG | |
|---|---|---|
| Compression | Usually none (optional RLE for 4 and 8-bit images) | Lossy DCT compression with adjustable quality |
| Size of a 1920 × 1080 photo | about 5.9 MB at 24 bits per pixel | about 0.2 to 0.8 MB at quality 85 to 92 |
| Transparency | Possible in 32-bit files, poorly supported | Not supported |
| Support | Windows, most editors; rarely accepted by websites | Every browser, phone, camera, website and email client |
| Best for | Legacy software, raw screen captures, embedded devices | Photos and scans you want to share, upload or store |
How big is an uncompressed bitmap?
An uncompressed BMP stores every pixel, so its size is easy to predict: row size = ceil(width × bits per pixel ÷ 32) × 4 bytes, and file size ≈ row size × height + header (54 bytes plus a color table for 8-bit and lower). Each row is padded to a multiple of 4 bytes. For example a 24-bit 4000 × 3000 scan takes 12,000 × 3,000 = 36 MB, while the same picture as a quality 90 JPG is typically 2 to 4 MB.
Tips for the best result
- Screenshots, diagrams and pixel art with flat colors compress better and stay crisper as PNG. Use PNG to JPG or the Image Converter if you need another format.
- Resizing to 50% cuts the pixel count by four, which shrinks the JPG roughly four times as well. That is often the best way to get very small files.
- Avoid converting the same image to JPG over and over. Keep the BMP or a lossless copy as your master file and export JPGs from it.
- Need a specific size such as 100 KB? Run the JPG through the Image Compressor afterwards.
Frequently asked questions
How do I convert BMP to JPG for free?
Drop your BMP files into the converter above. Each bitmap is decoded by your browser and saved as a JPG at the quality you choose, then you can download the files one by one or together as a ZIP. There is no sign-up, watermark or file limit beyond your device's memory.
Why is a JPG so much smaller than a BMP?
Most BMP files store every pixel uncompressed, so a 1920 x 1080 picture at 24 bits per pixel takes about 6 MB no matter what it shows. JPG uses lossy compression that removes detail the eye barely notices, so the same picture is usually 200 KB to 800 KB, often 90 percent smaller or more.
Will converting BMP to JPG lose quality?
JPG is lossy, so a tiny amount of detail is discarded. At quality 85 to 95 photos look the same as the original. Sharp graphics such as screenshots with small text can show faint artifacts around edges; for those use a high quality setting or convert to PNG, which is lossless.
What quality setting should I use?
90 is a good default for photos and scans. Use 75 to 85 for web pages and email where small files matter, and 95 to 100 when you plan to print or edit the image further. The card under each file shows the exact output size so you can compare.
What happens to transparent areas in a 32-bit BMP?
JPG cannot store transparency, so transparent and semi-transparent pixels are blended onto the background color you choose, white by default. Pick black or any custom color to match where the image will be used.
Are my files uploaded to a server?
No. The conversion uses your browser's own image decoder and the Canvas API, so your bitmaps never leave your device. The tool keeps working offline after the page has loaded.
Can I convert a DIB file?
Yes. A DIB file is the same device-independent bitmap format as BMP with a different extension, so it converts the same way.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.