BMP to WEBP Image Converter

Old format in, modern format out

Few conversions jump across as many years as this one. BMP is a Windows bitmap format from the late 1980s that stores pixels with little or no compression. WEBP is a format introduced by Google in 2010 specifically to make web images lighter. Moving an image from one to the other can shrink it from many megabytes to a few hundred kilobytes, which is exactly what you want when a bitmap needs to appear on a website, in a web app, or inside an online store listing.

The BMP to WEBP Image Converter does that conversion on our server. Your bitmap is decoded, optionally resized, and encoded as WEBP using the encoder's most thorough compression method, then handed back to you as a .webp file.

Why WEBP for a former bitmap

• Size. WEBP's lossy mode generally produces smaller files than JPEG at similar visual quality, and both are vastly smaller than an uncompressed BMP.
• Web performance. Lighter images load faster, which matters for visitors on mobile data and for page-speed scores.
• Browser support. All current major browsers display WEBP, so the file works on modern websites without extra steps.
• Transparency support. WEBP can store an alpha channel, unlike JPEG, which is useful if you later edit the image.

Where WEBP is not the answer

WEBP is a web format first. Some older desktop programs, document editors, printers, government portals and photo kiosks still do not open it. If the image is going to be printed, attached to an official application, or opened in old software, a JPEG will travel further; use BMP to JPEG for that. If you need a pixel-perfect copy for analysis or archiving, keep the BMP or use a lossless format, because this page writes lossy WEBP controlled by the quality slider.

Know the size ceiling before you start

Bitmaps are big, and the server accepts at most 10 MB per uploaded file. A typical 24-bit BMP spends about 3 bytes per pixel, so the ceiling corresponds to roughly 3.3 million pixels. A 1920 by 1080 screen capture as BMP fits comfortably at around 6 MB; a 4000 by 3000 scan does not. For oversized bitmaps, export a smaller copy from the original program first.

The upload box on this page is set to BMP images, so your file dialog lists your bitmaps straight away. You can also drag a BMP from a folder onto the upload area.

Configuration for web-ready output

The Configuration card opens with Convert Format set to WEBP. Here is how to use the remaining controls for web publishing:

Converting BMP to WEBP

1. Set Quality and, if needed, a Resize Unit with Width and Height.
2. Drag your bitmaps onto Select Images or press Select File.
3. Each file appears in the Upload Queue with its original size and pixel dimensions.
4. Click Process on one card to test your settings on a single image.
5. Satisfied? Press Process Queue to convert the remaining images in one request.
6. Open the output preview by clicking the thumbnail, check edges and text, then press Download.
7. For inline use in HTML or CSS, Copy Base64 copies a ready data URL. Keep this for small images only, since Base64 adds about a third to the size.

Bitmaps hosted somewhere online can be queued with From URL, one address per line, followed by Process in that panel.

Reading the savings

The output badge shows the new file weight with a down arrow and a percentage. With bitmaps the figure is often above 90%, because you are moving from essentially uncompressed pixels to a modern compressed format. If the saving seems small, the BMP may have been tiny already, or the quality is set very high; try 80%.

Also compare the output dimensions on the card with what you entered. Old bitmaps from scanners and screen captures are often much larger in pixels than any web layout needs, so the biggest win usually comes from combining the format change with a sensible Pixel width rather than from fine-tuning the slider.

Recommended practice

• Resize to the real display size. Shipping a 4000 pixel image to a 800 pixel slot wastes bandwidth even in WEBP.
• Test one representative image before a batch and keep the settings that look right.
• Keep the original BMP if it is the only lossless master.
• Rename files after downloading; names get a random prefix, and URL-sourced files lose their original name.

Things to avoid

• Sending WEBP to printers, older Office versions or portals that list only JPG or PNG.
• Setting Quality very low on graphics with text; letters get soft edges.
• Uploading bitmaps over 10 MB.
• Expecting the DPI field to change how big the image looks on a website.

Limitations

• Inputs: JPG, JPEG, PNG, GIF, WEBP, JIFF and BMP, up to 10 MB each.
• Whole numbers only for Width, Height and DPI.
• The physical units Inch, Centimeter and Millimeter use the DPI field (96 if empty) to calculate pixels, and need both dimensions.
• A queue run applies the same settings to every file, and a single failure makes the batch return an error.
• Metadata is stripped from outputs by default.
• There is no crop, rotate, flip or zoom tool on this page.

Privacy note

All conversion takes place on our server, not in your browser. The uploaded bitmap is processed by a server-side image library, the WEBP is sent back inside the response as Base64, and the temporary server copy is deleted once that response is prepared.

See also Convert to WEBP, which takes JPG, PNG and GIF sources as well.

Frequently Asked Questions