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TIFF to BMP converter

Convert TIFF images to BMP format

No watermarkFree & unlimited
All processing happens in your browser. No data is sent to any server.

Two uncompressed raster containers, one in and one out: this conversion is mostly a change of wrapper. The TIFF parser in this page reads the first image directory and rebuilds the pixels; a BMP writer then emits a 54-byte BITMAPFILEHEADER and BITMAPINFOHEADER pair followed by 24-bit BGR rows stored bottom-up with each row padded to a multiple of four bytes. The output is within a hundred bytes of the input for the same dimensions, so nothing is gained in size. What is gained is compatibility with old Windows software and anything that reads a device-independent bitmap.

Key facts about TIFF to BMP converter

Key facts about TIFF to BMP converter
Output size formula54 + ceil(width x 3 / 4) x 4 x height. A 1920x1080 image is exactly 6,220,854 bytes.
Versus the sourceThe same pixels as an uncompressed TIFF occupy 6,220,934 bytes, so the BMP is 80 bytes smaller. No real change.
Pixel layout24 bits per pixel in BGR order, rows written bottom to top, each row padded to a 4-byte boundary.
TransparencyNo alpha at 24 bits. A four-sample TIFF loses its alpha and transparent areas are written as black.
CompressionBI_RGB, meaning none. RLE4, RLE8 and BITFIELDS variants are not produced by this writer.
Stated resolutionThe header records 2835 pixels per metre on both axes, which is 72 DPI, regardless of what the TIFF implied.
Colour tableNone. A 24-bit BMP indexes nothing, so palette reduction never happens on this pair.
Source requirementThe TIFF must be uncompressed and 8 bits per sample. LZW or Deflate scans are refused with a message.
PagesThe reader stops at the first image directory, so multi-page document TIFFs yield a single bitmap.
Practical ceilingBoth formats are raw, so a 6000x4000 conversion allocates about 72 MB twice over in memory.
Opens natively inWindows Paint and Photos, macOS Preview, GIMP, IrfanView, and any Win32 app that loads a DIB.

What happens to your file

No network call touches the image. The file is read into an ArrayBuffer with the File API, decoded by the baseline TIFF reader compiled into this page, and painted into a canvas. The BMP is then assembled byte by byte into a DataView in the same tab, using getImageData to fetch the pixels back out of the canvas. The finished buffer becomes a Blob and a download link. Nothing is cached, uploaded or shared, and there is no server-side component to this tool at all.

About this tool

  1. 1

    Choose the TIFF

    Drag a .tif or .tiff file in or click to browse. A batch of up to twenty files is accepted.

  2. 2

    Decide on dimensions

    Because BMP size scales purely with pixel count, a size preset is the only lever that changes the output size.

  3. 3

    Convert

    The reader decodes the scan and the writer emits the header, then the padded BGR rows in reverse order.

  4. 4

    Download the bitmap

    Save the .bmp, or collect several results as one ZIP file built locally in the page.

Specs & compatibility
Input and outputTakes .tiff and .tif only (image/tiff) and returns .bmp with the image/bmp type; any other extension is refused before decoding.
Conversion pathTIFF to BMP runs in three steps: the page's own baseline parser reads the IFD and rebuilds the pixels, because no browser decodes TIFF; the pixels land on a 2D canvas in this tab; then getImageData feeds a 24-bit BI_RGB writer that assembles the file in page memory.
Browser supportThe TIFF side needs no browser support at all, only a baseline uncompressed source, because LZW, Deflate and JPEG-in-TIFF files stop with an error, while writing the BMP needs nothing from the browser, the bytes being assembled in the page.
Controls for this pairNo quality slider, BMP not being a lossy target here, so the max-dimension presets from 3840 down to 200 px are the only way to hold the BMP down in size against the TIFF.
Batch, caps and namingTwenty TIFF files per run at 500 MB each; one result downloads as a single BMP, several as converted-bmp-files.zip, zipped by JSZip 3.10 in page memory.
Device ceilingThe canvas caps it: past roughly 16,384 px a side Chromium refuses the bitmap and iPhone Safari gives up sooner, so an oversized TIFF fails before any BMP bytes exist.
  • Do not expect a smaller file. Both sides of this conversion store every pixel literally, so the only way to reduce the output is to reduce the dimensions.
  • If the destination software is fussy about alpha, this pair is useful precisely because it guarantees a flat 24-bit image with no fourth channel.
  • Check anything with transparency before converting: those regions arrive black rather than white, which is easy to miss on a dark scan.
  • The 72 DPI written into the header is a constant, not a reading of your scan. Set the true print resolution in whatever application places the bitmap.
  • For archiving, keep the TIFF. It is the format with room for tags, pages and profiles; BMP is a delivery wrapper for legacy tools.
  • Feed a legacy Windows application, industrial controller or embedded display tool that accepts only a plain device-independent bitmap.
  • Prepare an input for a course exercise or a computer-vision assignment that expects raw uncompressed pixel data with a simple header.
  • Hand a scanned texture to older 3D or game tooling whose importer predates PNG and TIFF support.
Because neither file compresses anything. The TIFF this tool accepts is baseline uncompressed at three bytes per pixel, and the BMP writer emits three bytes per pixel as well, differing only in header length and row padding. For a 1920x1080 image the gap works out at eighty bytes. If you want a smaller file, choose the PNG, JPG or WebP target instead.
A 24-bit BMP has no alpha channel, so it cannot be stored. The writer reads the red, green and blue bytes from the canvas and ignores the fourth. Fully transparent pixels sit at zero in every channel on an untouched canvas, so they are written as black. Composite the image onto a background colour in an editor first if black is wrong for your use.
It should not be. BMP traditionally stores its rows from the bottom up, and the writer does exactly that by iterating the canvas rows in reverse, so viewers see it the right way round. If a particular tool shows it inverted, that tool is assuming a top-down BMP, which is signalled by a negative height field that this writer never emits.
Not from this page. The writer is fixed at 24 bits per pixel with BI_RGB compression, which is the most widely readable BMP variant. The 32-bit BITFIELDS layout that carries alpha is understood by fewer old applications, and old applications are the main reason to want BMP at all. Use PNG when alpha matters.
Only nominally. Both resolution fields are hard-coded to 2835 pixels per metre, the standard 72 DPI value, and nothing about your TIFF influences them. Most viewers ignore these fields entirely and simply show the pixels. When physical size matters, set it in the application that places or prints the bitmap.
The reader supports the uncompressed baseline layout with eight bits per sample. Anything saved with LZW, PackBits, Deflate or JPEG compression is stopped before decoding, and 16-bit-per-channel files decode incorrectly. Re-save from your editor as an 8-bit uncompressed TIFF and the conversion completes without complaint.

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