Written by Jennifer Walsh. Reviewed for technical accuracy by Shubham Dixit, Independent Expert in Email Forensics and Data File Conversion.
Shubham is an independent external reviewer and not an employee of PCDOTS.
Quick answer. Paint converts a BMP to TIFF free, and IrfanView or ImageMagick handle a whole folder. Both formats are lossless so the picture is identical, but TIFF adds LZW compression that usually makes the file smaller than the BMP, plus the resolution and metadata that print and archive work need.
On this page
Why convert BMP to TIFF at all?
Here is the honest starting point, because a lot of guides get it backwards. BMP and TIFF are both lossless raster formats, so a picture is exactly the same quality in either one. Converting a BMP to TIFF does not make it sharper or better, and a BMP does not somehow print badly. The pixels are identical.
What differs is how useful each file is to work with. BMP is an old and very plain format, it stores the raw pixels and little else. TIFF is a proper working and archive container, it supports lossless compression, it carries resolution and colour metadata that a printer reads, it handles CMYK, and it can hold several images in one file. So you convert not for quality, which is unchanged, but for everything TIFF adds around the picture, which is what print shops, scanners and archives actually need.
Quality is identical either way. Everything else is on TIFF’s side.
“BMP and TIFF store the same lossless pixels, so the conversion is not about picture quality at all, it is about the container. A BMP is essentially raw bytes with almost nothing around them, whereas TIFF wraps the same image with lossless compression and proper metadata, which is why the TIFF is usually the smaller and the more portable of the two. For anything headed to print or long term storage, the documented and widely read format is the one worth keeping.” Shubham Dixit, Data File reviewer (draft, pending approval)
The file usually gets smaller
This is the part that surprises people, and it is the opposite of what happens with most conversions to TIFF. Because BMP stores pixels uncompressed, it is a bloated file for what it contains. TIFF supports LZW and ZIP compression, both of which are lossless, so they throw nothing away, yet they pack the same image into far less space.
So a large BMP commonly becomes a noticeably smaller TIFF with no change to the picture at all. The one setting to get right is compression, choose LZW rather than uncompressed when you save, since uncompressed TIFF hands back all the bloat you were trying to leave behind. Resolution should already be correct in the BMP, and a conversion carries it across unchanged.
Convert BMP to TIFF free
You do not need to buy anything for this, and for a single file Windows already has what you need.
Use Microsoft Paint. Unlike some formats, Paint opens BMP perfectly well. Open the file in Paint, go to File then Save as, and choose TIFF. That is the whole job for one image, and the result is lossless with no quality difference whatsoever.
Use IrfanView for a folder. Paint only does one file at a time, so for a batch reach for IrfanView, which is free for personal use and has had a batch conversion mode for years. Point it at a folder, set TIFF as the output, choose a destination and run it.
Use ImageMagick from the command line. A single instruction converts a whole directory, for example magick mogrify -format tif *.bmp, which is ideal for this technical desktop audience and can also combine images into one multi page TIFF.
On a Mac, use Preview. Open the BMP in Preview, choose File then Export, and pick TIFF, setting the compression before you save.
Many BMP files into one TIFF
One genuinely useful trick that BMP cannot do at all. TIFF can hold several images inside a single file, which is exactly how scanned multi page documents are stored. So if you have a stack of BMP scans, one per page, you can combine them into a single multi page TIFF rather than juggling dozens of separate files.
ImageMagick does this from one command, and most dedicated converters offer it as an option when you export. It is worth knowing about if your BMP files are really the pages of one document rather than unrelated images, since a single TIFF is far easier to file, email and archive than a folder full of loose pages.
A single multipage TIFF beats a folder of loose pages to file and archive.
Convert a folder of BMP files in bulk
If a command line is not for you and you would rather see the images before committing, a desktop converter does the same batch through an interface. The PCDOTS Image Converter loads a folder of BMP files, previews them, and writes a TIFF for each in a single run on your own PC with nothing uploaded. It carries the pixels across unchanged, which as above means the picture is preserved exactly while the file typically shrinks. There is a free version to try on your own files first.
The bulk route, for a folder of BMP files in a single run.
Here are the steps with the screens.
Step 1. Install and run the converter on your Windows PC.
Step 2. Click Open, choose BMP, and add your files or a whole folder, then preview them.
Step 3. Click Export and select TIFF from the list.
Step 4. Browse to a destination and click Save.
The same tool covers the neighbouring jobs, so there are guides to convert JPG to TIFF, to convert PNG to TIFF, and to convert BMP to WebP when you want a small web friendly file instead.
The methods compared
Match the route to how many files you have.
| Method | Best for | Good to know |
|---|---|---|
| Paint or Preview | One image, free | Built in, nothing to install |
| IrfanView or ImageMagick | A folder, free | Batch, and multi page too |
| Batch converter | A folder, no command line | Previews first, runs offline |
Frequently asked questions
How do I convert a BMP file to TIFF for free?
On Windows, open the image in Paint and use Save as, then TIFF. For a whole folder, IrfanView and ImageMagick both batch convert free, and on a Mac, Preview exports TIFF.
Does converting BMP to TIFF lose quality?
No. Both BMP and TIFF are lossless, so the pixels transfer exactly and nothing is lost. Use LZW compression on the TIFF, which is also lossless and makes the file smaller.
Why is my TIFF smaller than the BMP?
Because BMP stores pixels uncompressed while TIFF can compress them losslessly with LZW or ZIP. Same picture, less space, which is one of the better reasons to convert.
Can I combine several BMP files into one TIFF?
Yes. TIFF supports multiple pages in a single file, so a set of BMP scans can become one multi page TIFF. ImageMagick and most converters offer this.
Can I convert BMP to TIFF on a Mac?
Yes, with Preview, which is built into macOS. Open the BMP, choose File then Export, and select TIFF. The PCDOTS converter itself is Windows only.
Is Paint good enough for this?
For a single file, yes, and it is lossless, so there is no quality penalty. Its only real limit is that it converts one image at a time, so for a folder use a batch tool instead.
Smaller file, same picture
The thing to hold on to is that this conversion costs you nothing in quality and usually saves you space. BMP and TIFF carry the same lossless pixels, so the image is untouched, and because TIFF compresses losslessly while BMP does not, the TIFF you end up with is generally the smaller file, with resolution, colour data and multi page support that BMP never had. Use Paint for one, a free batch tool for a folder, choose LZW when you save, and you come away with a leaner, more useful file and exactly the picture you started with.
