Picovert

Convert BMP to WebP Free — Reduce File Size by 90%

By Picovert Team2026-01-264 min read

BMP files are some of the largest image files you'll encounter. A single BMP screenshot can be 3–10 MB because the format stores every pixel without compression. WebP converts that same image to 300 KB–1 MB while keeping it visually identical. This guide explains how to convert BMP to WebP free, and when to pick WebP vs other formats.

How to Convert BMP to WebP Free

  1. Open Picovert's BMP to WebP converter — free, no account, no install. Everything runs in your browser.
  2. Drop your BMP file (or multiple files for batch conversion).
  3. The converter processes the file and offers a WebP download.
  4. Download the WebP file — typically 70–90% smaller than the original BMP.

Why BMP Files Are So Large

BMP (Bitmap) is an uncompressed raster format created by Microsoft. Every pixel is stored as raw RGB data, which means:

  • A 1920×1080 BMP at 24-bit color takes approximately 6 MB
  • A 4K (3840×2160) BMP at 24-bit color takes approximately 24 MB
  • No lossy or lossless compression is applied by default
  • Files are not suitable for web use, email, or cloud storage

BMP was designed for Windows internal use — paint programs, system screenshots, and clipboard storage. It was never meant to be shared or published.

How Much Smaller Is WebP vs BMP?

WebP uses both lossy and lossless compression. Converting from BMP:

  • Lossy WebP: typically 85–95% smaller than BMP. A 6 MB BMP becomes ~400 KB WebP. Ideal for photos and web images where perfect pixel accuracy isn't needed.
  • Lossless WebP: typically 50–70% smaller than BMP. A 6 MB BMP becomes ~1.5–2 MB WebP. Every pixel is identical to the original.

For most use cases, lossy WebP at 80–90% quality is indistinguishable from the original BMP while being dramatically smaller.

BMP vs WebP vs PNG vs JPG

  • BMP: Uncompressed, huge file size. Only use for Windows-specific workflows (e.g., legacy software input).
  • WebP: Best compression for web. Supports transparency and animation. Supported in all modern browsers and most apps since 2022.
  • PNG: Lossless compression. Larger than WebP but better compatibility — works everywhere including older apps, Word, Figma.
  • JPG: Lossy compression. No transparency support. Best for photos, not for screenshots or images with text/flat color.

Does BMP Support Transparency?

Standard BMP (24-bit) does not support transparency. A 32-bit BMP can store an alpha channel, but almost no software reads it correctly. If your BMP has a white background that you want to remove, convert to WebP or PNG first, then use Picovert's background remover.

When to Use WebP vs PNG After Converting from BMP

  • Use WebP when the image is going on a website, in a web app, or being shared digitally. WebP gives the smallest file with great quality.
  • Use PNG when you need to open the file in older software (Photoshop pre-23.2, Office 2019), send via email, or insert into documents. PNG has wider app support.
  • Use JPG when the image is a photo with no transparency and you need maximum compatibility. JPG is universally supported.

Batch Convert BMP to WebP

If you have multiple BMP files — for example, a folder of screenshots or scanned images — you can drop them all at once into the BMP to WebP converter. All files are processed client-side in your browser, so nothing is uploaded to a server.

Compress WebP Further After Converting

If the resulting WebP file is still larger than you'd like, run it through Picovert's image compressor. Adjusting the quality slider down from 90% to 75–80% typically cuts another 30–50% off the size while keeping the image looking sharp.