Bulk BMP to WebP Converter
Convert uncompressed BMP images to WebP and shrink file sizes by 90% or more. Without any visible quality loss. BMP stores raw pixel data with zero compression, making it one of the heaviest formats in existence. WebP replaces that bulk with modern compression and full browser support.
Your images
0 images addedConvert BMP to WebP in 3 Steps
No account, no install, no queue. Drop your BMP files in and the WebP versions are ready to download.
- Step 1
Drop your images in
Drag files onto the page, click to browse, or drop in a ZIP and every supported image inside is pulled out. JPG, PNG, WebP, AVIF, HEIC, GIF and BMP all work, mixed together in the same batch.
- Step 2
Adjust if you want to
Choose your output format and drag the quality slider. That is the whole setup. Settings holds a KB target, resizing and batch renaming if you want them, and can stay closed if you do not.
- Step 3
Download your WebP files
Conversion starts on its own, so there is usually nothing to press. Batches over 40 wait for one click so nothing runs away with your machine. Download files one at a time or take the whole batch as a single ZIP.
Why Convert BMP to WebP?
BMP (Bitmap) is the original Windows image format. A raw, uncompressed pixel dump with essentially zero compression applied. A typical 1920×1080 BMP file weighs in at around 6 MB. The same image as WebP sits under 200 KB at quality 90. That's a 97% size reduction with no meaningful visual difference. BMP exists today almost exclusively as an intermediate format for Windows applications and legacy workflows. The moment those images need to go anywhere online, a website, a CMS, an email, a shared drive, BMP becomes a liability. WebP is the modern, compressed, web-native format that accepts BMP content without any of the file size overhead.
Windows Bitmap Format
BMP was introduced with Windows 1.0 in the late 1980s as a simple pixel storage format for the Windows GUI. It stores raw, uncompressed pixel data. Every pixel takes the same fixed amount of storage regardless of image content. A 24-bit BMP image at 1920×1080 pixels always weighs approximately 6 MB, regardless of whether it's a complex photograph or a simple solid-color graphic. BMP has no compression, no quality tuning, and no concept of web delivery.
WebP Image Format
WebP is Google's modern web-optimized image format. 25–34% smaller than JPEG and dramatically smaller than BMP for equivalent visual quality. It supports both lossy and lossless compression modes with full alpha transparency, making it suitable for any type of BMP content. Every modern browser supports WebP, as does virtually every web platform, CMS, and image processing pipeline. It's the practical, efficient format that BMP should have always been for web use.
6 MB BMP. Under 200 KB WebP.
BMP's zero-compression design means even modest images are enormous. WebP's modern codec shrinks them to a fraction of their original size. With no meaningful visual trade-off.
True Bulk Conversion
Convert 10 or 500+ BMP files to WebP in one batch. No file limits, though note that BMP files are large by design, so processing large batches may take longer than other formats.
100% Private & Secure
Client-side only. Your BMP files never leave your device. No server, no cloud, no third party sees your images at any point during conversion.
Adjustable Quality Control
Set WebP quality from 1 to 100. For BMP source images, quality 85–90 delivers visually identical results at 90–97% smaller file sizes. The before/after slider lets you verify exactly what's being saved before committing to a batch.
ZIP Upload & Download
Upload a ZIP of BMP files. Download all converted WebP images as a single ZIP. Ideal for bulk legacy asset migrations and Windows-to-web workflow conversions.
Batch File Renaming
Set a custom prefix, separator, numbering, and.webp extension. Preview the filename pattern before downloading your converted batch. Essential when dealing with auto-generated BMP filenames.
the maximum size option
Need WebP files under 150 KB for a specific upload limit or CMS constraint? Set a target KB and the tool automatically finds the optimal quality per image. Starting from the massive headroom BMP's zero-compression baseline provides.
Works on Every Device
Windows, Mac, Linux, Chromebook, iPhone, Android. Any modern browser runs the conversion with no installation required. Move BMP files off Windows without needing Windows software.
Selective Processing
Upload a batch of BMP files and select only the specific images you need as WebP. Only those are converted and downloaded. No pre-filtering of your library required.
Full Transparency Preserved
BMP files can contain transparency data (32-bit BMP with alpha channel). WebP preserves that transparency fully. If you need to flatten transparency to white for maximum compatibility, use our BMP to JPEG converter instead.
How SmallerImages Compares
Here's how our free BMP to WebP converter stacks up against typical online tools.
| Feature | SmallerImages | Typical Converter |
|---|---|---|
| Bulk conversion (200+ files) | Yes | No 10–20 file limit |
| Browser-based (no server uploads) | Yes | No Files uploaded to server |
| Full transparency preserved in WebP output | Yes | Varies. May drop alpha channel |
| ZIP file upload & download | Yes | No |
| Adjustable quality (1–100) | Yes | Limited presets only |
| Target file size (KB) | Yes | No |
| Batch file renaming | Yes | No |
| Before/after comparison | Yes | No |
| Selective processing | Yes | No |
| 100% free, no signup | Yes | Freemium / ads |
| Ad-free | Yes | No |
When You Need BMP to WebP
BMP files almost always come from Windows-native workflows. When that content needs to go anywhere online, BMP to WebP is the most efficient conversion path.
Windows Screenshot & Screen Capture Workflows
Windows tools like Paint and some screenshot utilities default to saving images as BMP. If you're capturing screens for documentation, tutorials, or reporting and need to publish them to a website or share them online, converting to WebP first removes the enormous file size overhead BMP carries while preserving every pixel of detail.
Legacy Windows Application Asset Export
Many older Windows applications, industrial software, medical systems, CAD tools, custom business applications, export images only in BMP format. Converting those exports to WebP makes them usable for web publishing, documentation sites, and any modern delivery pipeline without carrying the raw uncompressed file size.
Game & Software Asset Development
Game engines and some design tools work with BMP as an intermediate format for textures and UI assets during development. Converting BMP assets to WebP is a standard step when those assets need to be delivered via a web-based interface, player dashboard, or online game store listing.
Scanning & Document Imaging Workflows
Document scanners on Windows frequently output BMP files by default. Particularly in enterprise, legal, and medical environments. Converting scanned BMP images to WebP before web publication or cloud storage reduces file sizes dramatically while keeping the images fully viewable in any browser.
Web Publishing from Windows-Native Tools
Microsoft Office, older versions of Visio, and various Windows-native reporting tools sometimes export charts, diagrams, and graphics as BMP. Converting those exports to WebP makes them suitable for embedding on websites, intranets, and documentation portals without the enormous raw file sizes that BMP produces.
Reducing Cloud Storage & Transfer Costs
BMP files consume storage and bandwidth at an extraordinary rate relative to their content. A folder of 100 BMP screenshots can easily exceed 500 MB. Converting that same set to WebP typically brings it under 10 MB. A meaningful reduction in cloud storage costs, email attachment sizes, and upload times.
Trusted for BMP to WebP Conversion
Real feedback from people converting BMP to WebP every week, from teams in the UK, US, India, Japan, Pakistan, the UAE and beyond.
The ZIP support is underrated. Our photographer sends everything as one archive. I drop the whole.zip in, it pulls out every BMP file, converts them to WebP, and hands back a single ZIP to download. Two clicks for the entire job.
The interface tells you what is actually happening, which file, what state, why something was skipped. That sounds basic but almost nothing else in this space does it.
I had just over 300 BMP files from a product shoot that all needed to be WebP. Dropped the lot in, walked away, came back to a finished batch. No queue, no "upgrade to convert more than 20 files" wall.
Cut about 60% off our image payload converting BMP to WebP. No visible difference to customers, measurably faster pages.
I was sceptical about the target size mode but it works properly. Asked for under 200 KB and every WebP file came in just under, with the quality it could manage at that budget rather than some fixed preset.
a BMP is often 10x the size it needs to be. Moving them to WebP was the obvious fix, I just needed something that would do it in bulk without a subscription. This does.
Our client contracts forbid uploading unreleased assets to third-party servers, which rules out almost every online converter. This one runs in the browser, so the BMP files never leave the machine. I checked the network tab myself before I trusted it.
Selective processing is the feature I did not know I wanted. Half my folder was already WebP; it skipped those and only converted the BMP files, without stopping the batch to ask me about it.
Tried the usual suspects including a paid TinyPNG plan. The difference here is no file cap and no watermark on the free tier, because there is no paid tier to upsell you to.
Runs fine on a locked-down work laptop where I cannot install anything. That is the entire reason I found this in the first place.
What surprised me was that it stays responsive during a big batch. The page does not lock up, the progress updates, and I can keep working in another tab.
Uploaded a nested ZIP straight from a client's Dropbox export. It found every BMP image inside the subfolders, converted them, and gave me one tidy WebP archive back.
BMP to WebP Conversion and Compression Explained
What changes when you convert BMP to WebP, what it costs, and how to pick a quality setting you will not regret.
A BMP stores raw pixel data with no compression worth the name, which is why a 4000 pixel scan can run past 45 MB. Nothing about that helps you. Converting to WebP keeps the image and discards the waste, usually cutting the file to a tenth of its original size with no change you can see at normal viewing distance.
Both formats are lossy, so the conversion re-encodes rather than copies. Keep quality at 85 or above if the file is going to be edited again, and use the before and after slider to check the first image of a batch before you commit to the rest.
Set quality once and it applies to the whole batch, so a folder of two hundred files takes the same number of decisions as one. Everything runs on your own machine, so speed depends on your processor rather than on how busy a server is. If you are working to a hard limit, such as a content management system that rejects anything over 200 KB, open Settings and set a maximum file size instead of a quality percentage. The encoder then searches for the best quality that fits your budget, file by file.
All Formats. One Tool.
BMP to WebP is one of twenty-four conversion paths here, and each one has its own page with defaults already set for that pair. Whichever you land on, the tool behind it is the same: it accepts JPG, PNG, WebP, AVIF, HEIC, GIF and BMP, reads ZIP archives, and handles up to 500 images in a single batch.
Conversion runs in your browser using your own processor, so nothing is uploaded, nothing is queued behind other people, and there is no account, no watermark and no daily cap. Close the tab and the files are gone from memory; they were never anywhere else.
If you need a smaller file rather than a different format, the image compressor keeps your originals and works to a quality level or a size in kilobytes. To change dimensions, the image resizer handles fit, fill and crop, or stretch across a whole folder at once.
Frequently Asked Questions
Quick answers about converting BMP to WebP.
Is it safe to convert BMP to WebP on SmallerImages?
How much smaller will WebP files be compared to my BMP files?
Why are BMP files so large?
Will I lose any quality converting from BMP to WebP?
Does WebP preserve BMP transparency?
When would I use BMP to WebP vs BMP to PNG?
Can I also convert BMP to PNG, JPEG, or AVIF?
How many BMP files can I convert at once?
Is SmallerImages completely free?
Can I upload a ZIP of BMP files?
6 MB Per Image Is Not a Storage Strategy. It's a Problem.
BMP's zero-compression design made sense in 1987 when storage was slow and processors were simple. Today it's just waste. WebP takes those same images and delivers them at under 200 KB. Same quality, 97% less data. Convert your BMP library for free, privately, without uploading a single file.
Convert BMP to WebP Now