Output format
90%
Resize
Convert BMP to WEBP Online Free — Fast Batch Conversion
How to Convert Images Online
1Upload your BMP file
Drag and drop one or more BMP files onto the converter, or click to browse. Files up to 1 GB supported. .dib files accepted too.
2Choose lossy or lossless
Lossy Q 80–85 is best for photos and gradients. Lossless is best for screenshots, UI, text, and palettized BMPs.
3Download your WebP
Your WebP file is ready in under a second. Batch jobs return a ZIP. Files are deleted from the server immediately after download.
Supported Image Formats
WebP
Modern image format by Google. Up to 30% smaller than JPG with the same quality.
BMP
Uncompressed bitmap format. Maximum quality but very large file size.
HEIC
Apple photo format used by iPhone and iPad. High quality with small file size.
HEIF
High Efficiency Image Format — same as HEIC, used on Apple devices.
PNG
Lossless format that preserves every pixel. Best for screenshots and logos.
JPG
Universal format for photos. Supported everywhere, great balance between quality and file size.
GIF
Classic format for simple animations. Supports transparency and up to 256 colors.
TIFF
Professional lossless format used in printing and photography.
AVIF
Next-gen format with excellent compression. Up to 50% smaller than JPG.
PPM
Portable Pixmap format used in Unix/Linux environments.
HDR
High Dynamic Range format storing extended brightness data.
FITS
Flexible Image Transport System used in astronomy and science.
PDF
Portable Document Format. Convert PDF pages to JPG, PNG or WebP images.
AVIF vs WebP vs HEIC vs JPG
Quick comparison to help you choose the right format
AVIF
- Size: Up to 50% smaller than JPG
- Browsers: Chrome, Firefox, Safari
- Transparency: ✓
- Best for: Web performance
WebP
- Size: 25-35% smaller than JPG
- Browsers: All modern browsers
- Transparency: ✓
- Best for: Web compatibility
HEIC
- Size: ~50% smaller than JPG
- Browsers: Safari only
- Transparency: ✓
- Best for: iPhone storage
JPG
- Size: Baseline
- Browsers: All browsers & apps
- Transparency: ✗
- Best for: Universal sharing
Frequently Asked Questions
- Will converting BMP to WebP lose quality?
- No — if you choose lossless mode, every pixel is reproduced exactly. In lossy mode at Q 80–85, differences are imperceptible on photographic content. Visible quality loss only occurs at very low Q values (below 60).
- How much smaller will my WebP be compared to BMP?
- For photos: typically 20–50× smaller (95–98% reduction). A 1920×1080 BMP at 5.93 MB becomes 150–300 KB at Q 80 lossy. For screenshots and UI graphics in lossless mode: often 50–120× smaller due to WebP's color-indexing compression.
- Should I choose lossy or lossless for my BMP?
- Lossy Q 80–85 for photographs and gradients. Lossless for screenshots, UI, text, line art, and any palettized BMP (1/4/8-bit). Near-lossless for logos and diagrams with sharp edges plus subtle gradients.
- Does WebP support transparency like 32-bit BMP?
- Yes — and more cleanly. Standard 24-bit BMP has no transparency at all. 32-bit BMP technically has a 4th byte but it is officially 'reserved' unless a BITMAPV4/V5 header or BI_BITFIELDS mask explicitly declares it as alpha. Convertify detects and preserves declared alpha channels and outputs them to the WebP ALPH chunk.
- Can I convert multiple BMP files at once?
- Yes. Upload multiple BMP files simultaneously and Convertify processes them in parallel. Batch results are returned as a ZIP archive.
- What is a .DIB file — can I convert it?
- A .dib file is a Device-Independent Bitmap — a BMP without the 14-byte file header, produced by the Windows Clipboard (CF_DIB, CF_DIBV5) and some resource editors. Convertify accepts .dib files and reconstructs the missing header automatically.
- Does WebP work in all browsers in 2026?
- 96.4% global browser support (caniuse.com). Chrome, Firefox (65+), Safari (14+), and Edge all support WebP. The only holdout is classic Outlook Desktop for HTML email — use a <picture> fallback there.
- Why can't I use BMP files directly on my website?
- BMP files are not renderable by web browsers in <img> tags, and even if they were, a single 1080p BMP at ~6 MB would fail Google Lighthouse's 'Serve images in next-gen formats' audit and destroy your Core Web Vitals LCP score.
- Does Convertify store my BMP files?
- No. Files are processed server-side in isolated workers and deleted immediately after your download. Nothing is stored or logged.
- What BMP variants does Convertify support?
- All standard Windows BMP variants: BITMAPCOREHEADER (OS/2), BITMAPINFOHEADER (most common), BITMAPV4HEADER, and BITMAPV5HEADER including embedded ICC profiles. Bit depths 1, 4, 8, 16, 24, and 32-bit. BI_RGB and BI_BITFIELDS compression. Also .dib files (headerless BMP from Windows Clipboard).
Why BMP files are so large — and what WebP does differently
BMP (Bitmap) was created by Microsoft in 1990 for Windows 3.0. It stores every pixel as raw data with zero compression by default. The file-size formula for a 24-bit BMP is exact: width × height × 3 bytes, rounded up to a 4-byte row boundary. At 1920×1080 that is 6,220,854 bytes — nearly 6 MB for a single screenshot. WebP uses the VP8 video codec (lossy) or VP8L with LZ77 + Huffman coding (lossless) to eliminate that bloat. Google's measured benchmarks: lossy WebP is 25–34% smaller than JPEG at equal SSIM quality; lossless WebP is 26% smaller than PNG on average. Versus uncompressed BMP the gains are far larger — typically 20–50× for photos and 50–120× for screenshots.
BMP vs WebP — full technical comparison
| Feature | BMP | WebP |
|---|---|---|
| Compression | None (BI_RGB raw pixels) | VP8 lossy or VP8L lossless |
| 1920×1080 file size | ~5.93 MB (exact) | 150–300 KB lossy / 750 KB–1.2 MB lossless |
| 4K (3840×2160) file size | ~23.7 MB | 600 KB–1.2 MB lossy / 3–5 MB lossless |
| Size reduction vs BMP | — | 95–98% (photos), 98–99% (screenshots) |
| Transparency (alpha) | 24-bit: none / 32-bit: ambiguous | Full alpha — ALPH chunk or VP8L |
| Browser support (2026) | Not renderable on web | 96.4% global (caniuse.com) |
| Animation | No | Yes (animated WebP) |
| Lossless mode | Always (uncompressed) | Yes — VP8L, 26% smaller than PNG |
| Google Lighthouse flag | Flagged as 'avoid on web' | Recommended next-gen format |
| Color depth | 1, 4, 8, 16, 24, 32-bit | 8-bit ARGB (24-bit RGB + 8-bit alpha) |
| ICC color profile | V5 header only (rare) | ICCP chunk — preserved by Convertify |
| Open format | Yes (Microsoft DIB spec) | Yes (Google open-source, RFC 6386) |
Lossy or lossless — which to pick for your BMP
WebP supports both modes and the right choice depends on your BMP content. Use lossy Q 80–85 for photographs and any 24-bit BMP with gradients — you get the smallest file with no perceptible difference. At Q 80, lossy WebP is typically 65–70% smaller than an equivalent JPEG and 95–98% smaller than the source BMP. Use lossless for screenshots, UI mockups, text, line art, and any palettized BMP (1/4/8-bit color). VP8L's color-indexing transform crushes flat-color content dramatically — a 1080p screenshot BMP of 5.93 MB can become 50–200 KB lossless WebP. Use near-lossless for logos and diagrams with sharp edges plus subtle gradients — it eliminates JPEG-style ringing while compressing 60–80% better than lossless. Convertify defaults to lossy Q 82 with sharp_yuv enabled, which preserves fine detail better than standard YCbCr subsampling.
BMP file size benchmarks — exact numbers
BMP file sizes are deterministic: a 24-bit BMP at 640×480 is exactly 921,654 bytes (0.88 MB); at 1280×720 it is 2,764,854 bytes (2.64 MB); at 1920×1080 it is 6,220,854 bytes (5.93 MB); at 2560×1440 it is 11,059,254 bytes (10.55 MB); at 3840×2160 it is 24,883,254 bytes (23.73 MB). Converted to lossy WebP at Q 80 a 1080p photo BMP typically lands at 150–300 KB — a 20–40× reduction. The same image as lossless WebP sits at 750 KB–1.2 MB — still 5–8× smaller than BMP, with pixel-perfect fidelity. For screenshots the lossless ratio is far better: flat-color UI BMPs often compress 50–120× under VP8L's color-indexing transform.
BMP variants your converter needs to handle
Not all BMP files are the same. The most common is BITMAPINFOHEADER (40-byte DIB header, 24-bit BI_RGB) — what Microsoft Paint produces. Older OS/2 files use BITMAPCOREHEADER (12 bytes). BITMAPV4HEADER (108 bytes) adds gamma and CIEXYZ color endpoints; BITMAPV5HEADER (124 bytes) adds embedded ICC profiles — both are rare but exist in professional workflows. Color depths range from 1-bit monochrome to 32-bit. In 32-bit BMP the 4th byte is officially 'reserved' unless a V4/V5 header or BI_BITFIELDS mask explicitly declares an alpha channel — many converters silently discard this, turning transparent regions opaque or black. Convertify detects the header version, respects declared alpha masks, and passes ICC profiles through to the WebP ICCP chunk. .DIB files (Device-Independent Bitmaps from Windows Clipboard or resource files) are accepted too — they are headerless BMP payloads that Convertify reconstructs automatically.
How BMP to WebP conversion affects page speed and Core Web Vitals
Google uses Core Web Vitals as a ranking signal. The Largest Contentful Paint (LCP) metric measures how fast the main image on a page loads — and BMP is the worst possible choice. A 5.93 MB BMP on a page will fail LCP on almost any connection (LCP good threshold: ≤2.5 seconds). The 2025 HTTP Archive Web Almanac reports images are the LCP element on 85% of desktop pages, yet only 74% of desktop and 62% of mobile pages achieve good LCP. Converting that same image to 200 KB WebP can cut LCP by 2–4 seconds on mobile. Google's Lighthouse audit ('Serve images in next-gen formats') explicitly targets BMP — it flags every BMP on a page and reports potential savings. Bandwidth math: a single 1080p BMP at ~6 MB dropped to 250 KB saves 5.75 MB per view — at 1M views/month that is ~5.4 TB of CDN egress eliminated, worth $40–120/month on standard CDN pricing.
When BMP files still appear in 2026
BMP is narrowly but genuinely useful in several workflows. Microsoft Paint still exports BMP by default on all Windows versions. Windows GDI (Graphics Device Interface) uses BMP internally for screen captures via BitBlt, PrintWindow, and CF_DIB clipboard reads. Game development: retro toolchains (gfx2gba, GBTD for GBA) require BMP input; Elite: Dangerous saves F10 screenshots as BMP; older Blender and 3ds Max texture exports are BMP. Medical imaging: RadiAnt DICOM Viewer, MicroDicom, and Radiopaedia document BMP as a standard export for case reports and LMS content. Embedded systems: Waveshare e-paper displays and ESC/POS thermal printers require 1-bit BMP input. Scanner software: older Epson and Canon flatbed drivers default to BMP. All of these are legitimate sources of BMP files — and every one of them needs WebP before the file goes anywhere near a browser or email.
Converting BMP to WebP in code
If you need to automate BMP to WebP conversion in your own stack: Python with Pillow — 'from PIL import Image; Image.open("input.bmp").save("output.webp", quality=82, method=4)'. Command-line with cwebp — 'cwebp -q 82 -m 4 -sharp_yuv input.bmp -o output.webp'. Batch with ImageMagick — 'magick mogrify -format webp -quality 82 *.bmp'. Node.js with sharp (requires sharp-bmp for BMP support) — 'sharp("input.bmp").webp({quality:82,effort:4}).toFile("output.webp")'. Lossless mode in cwebp — 'cwebp -lossless -z 9 input.bmp -o output.webp'. Note: libvips has no native BMP loader — it routes BMP through ImageMagick (magickload). If your libvips build was compiled without ImageMagick (common on Alpine Docker images), BMP files will fail silently with 'is not a known file format'. Convertify's Rust + libvips backend handles this correctly on all BMP variants.
WebP browser support in 2026
WebP has 96.4% global browser support as of early 2026 (caniuse.com). Chrome has supported it since v32 (2014); Firefox since v65 (January 2019); Safari since v14 on macOS and iOS (September 2020); Edge since v18. Internet Explorer 11 is effectively dead after Windows 10 reached end-of-support in October 2025. The one remaining practical limitation is email clients: classic Outlook Desktop for Windows does not render WebP (New Outlook does). For HTML email, use a