ICO to BMP Converter

How to Convert ICO to BMP Online

1. Upload Your ICO File: Drag and drop or click "Add Files" to select Windows icon files. Multi-resolution ICOs that bundle 16×16, 32×32, 48×48, 64×64, 128×128, and 256×256 layers are accepted. Batch is supported — drop in a whole \System32 extract or icon library.
2. Pick Bit Depth and Compression Type: Choose 1-bit (monochrome), 8-bit (256-color indexed), or 16-bit color depth. Set the BMP compression type — None (uncompressed RGB, the most compatible) or Deflate for a smaller file. BMP is lossless; the layered ICO frame closest to your target size is unpacked into a single bitmap.
3. Resize and Set DPI (Optional): Pick a resolution preset, scale by percentage, or set custom width × height in pixels. Set DPI from 72 / 96 (screen) up to 150 / 200 / 300 / 600 / 1200 (print). Color palette size (2 / 4 / 8 / 16 / 32 / 64 / 128 / 256 colors) lets you generate indexed-color BMPs that mimic the original ICO palette exactly.
4. Convert and Download: Click Convert. Files convert in your browser session and download individually or as a ZIP — no sign-up, no watermark.

Why Convert ICO to BMP?

ICO is Microsoft's container format for application and shortcut icons — a single .ico file holds several bitmap layers at different sizes and color depths so Windows can pick the right one for the taskbar, desktop, file explorer, or Alt-Tab UI. BMP is the underlying flat-bitmap format Windows has shipped since 1990. Converting ICO → BMP unpacks one of those embedded layers into an editable, single-image bitmap.

• Editing icon artwork in legacy Windows tools — Paint, IrfanView, classic Photoshop plugins, and old MFC-era image editors read BMP natively but choke on the multi-layer ICO container. Convert to BMP, edit pixels, then re-pack with BMP to ICO when done.
• Image processing pipelines and OCR — OpenCV, ImageMagick scripts, Tesseract, and most computer-vision libraries expect single-frame inputs. BMP is the lowest-common-denominator lossless format — no codec surprises, no alpha quirks, no multi-page weirdness.
• Embedded systems and microcontroller displays — STM32 / ESP32 graphics libraries, e-paper drivers, and old printer firmware ship BMP parsers but rarely an ICO decoder. Flashing a splash screen or UI sprite usually means a 24-bit BMP.
• Reverse-engineering icons from .exe / .dll extracts — Tools like Resource Hacker dump icons as ICO. Converting to BMP gives you a flat raster you can diff, archive, or feed into asset-tracking workflows.
• Print and large-format reproduction — Blowing up a 256×256 ICO layer for sticker or signage print is easier from a fixed-DPI BMP than from the layered original. Set DPI explicitly and the printer driver behaves predictably.
• Preserving exact pixel data without compression — Unlike JPG or even PNG, uncompressed BMP stores raw RGB bytes. For pixel-art icons, dithered 8-bit palettes, and forensic image work, that bit-for-bit fidelity matters.

ICO vs BMP — Format Comparison

ICO Layer Sizes — Which One Becomes Your BMP?

Frequently Asked Questions

Which icon layer gets converted when an ICO has several sizes inside?

The converter picks the layer closest to your chosen output resolution. If you leave resolution at default, the largest layer (often 256×256) is unpacked so no detail is thrown away. Set a specific width × height (for example, 32×32) to grab that exact layer. To unpack every layer separately, run the conversion once per target size or split the ICO first with ICO to PNG and convert the PNGs to BMP.

Will transparency from the ICO survive in the BMP?

Partially. ICO uses either a 1-bit AND mask (hard edges) or a 32-bit alpha channel (soft edges, Vista+). BMP can carry 32-bit RGBA via the BITMAPV4HEADER, but many older Windows tools — including classic Paint pre-Windows 7 — render the alpha channel as solid black or white. If your target reader is one of those legacy tools, flatten transparency to a chosen background color before converting.

Why is my BMP so much larger than the original ICO?

ICO files compress their large layers (typically the 256×256 frame) as PNG inside the container. BMP defaults to uncompressed raw pixels: a 256×256 24-bit BMP is roughly 196 KB regardless of content. Use Deflate compression to shrink the BMP, or drop bit depth to 8-bit (256-color) for icons that only use a small palette — that alone cuts size by two-thirds.

Should I pick 8-bit, 24-bit, or 32-bit BMP?

8-bit (256-color indexed) is best for classic pixel-art icons, monochrome glyphs, and palette-locked artwork — smallest file, exact color match. 24-bit RGB is the safe default for any modern icon with gradients or photographic content. 32-bit RGBA preserves the alpha channel but only matters if the consumer actually reads alpha (modern editors yes, embedded firmware usually no).

Can I convert a Windows favicon (favicon.ico) to BMP?

Yes — favicons are standard ICO files, just typically 16×16 and 32×32 layers. Drop the favicon.ico in and the converter unpacks one of the embedded frames as a BMP. Note that some modern favicons are PNG-encoded inside the ICO container; that's handled transparently. For the reverse direction (e.g., turning artwork back into a favicon), see BMP to ICO.

Does the converter handle ICO files extracted from .exe and .dll files?

Yes — icons dumped from executables by Resource Hacker, IconViewer, or similar tools are normal ICO files and convert the same way. If the dumped file is a .icl (icon library) instead of .ico, extract the individual icons first; .icl is a different container format.

Why convert to BMP instead of PNG?

PNG is usually better — smaller, lossless, alpha-aware, and universally supported. Pick BMP when your target tool specifically demands it: legacy Windows imaging code, embedded display libraries that ship a BMP-only parser, certain CNC / laser engraver workflows, or forensic / archival pipelines that mandate raw-pixel uncompressed storage. For everything else, ICO to PNG is the better choice.

Can I batch convert hundreds of ICO files at once?

Yes — drop in entire icon archives, .exe extract folders, or theme bundles. Each file converts in parallel within your browser session and downloads individually or as a single ZIP. Settings (bit depth, DPI, target resolution) apply uniformly across the batch.