TIFF is the format that shows up when something was made carefully. A flatbed scanner set to archive quality, a fax server, a print shop asking for "a TIFF, not a JPG", a museum digitizing a collection. It is also the format that shows up as a 60 MB attachment nobody can open on their phone. Both of those facts come from the same design, and once you see how a TIFF is put together, deciding whether to keep one, convert it, or shrink it stops being guesswork.
This guide covers what a TIFF file is, why it gets so large, when it is still the right format, and the practical ways to make one small enough to send without wrecking the parts that matter. It sits under the image tools hub, alongside the guide to camera RAW files like CR2 and DNG, which are built on the same file structure.
TL;DR: TIFF (Tagged Image File Format) is a flexible container for high-quality raster images, usually stored uncompressed or with lossless compression, which is why scans and print files are so large: a letter-size color page at 300 dpi is about 25 MB of raw pixel data. Keep TIFF for archive masters, print production and fax or document systems. To shrink one for sharing, convert it: TIFF to JPG for photos and color scans, TIFF to PNG for black-and-white pages and graphics, and TIFF to PDF when a multi-page scan needs to stay one document. All three run client-side, nothing uploaded, free, no signup.
What is a TIFF file?
A TIFF file is a raster image container that stores pixels together with a set of numbered tags describing them: width, height, bit depth, color model, compression method, resolution and more. The name stands for Tagged Image File Format, and the tags are the whole idea. Instead of fixing one way to store an image, TIFF lets the file say how its own pixels are stored, and a reader follows those instructions.
The format was created by Aldus in the mid-1980s for desktop scanners and publishing software. The version everyone still implements is TIFF Revision 6.0, finalized on June 3, 1992. Adobe acquired Aldus in 1994 and has held the specification since, and the MIME type image/tiff is registered in RFC 3302. The .tif and .tiff extensions mean the same thing; the three-letter form is a leftover from the old DOS 8.3 filename limit.
Inside, a TIFF has a short header and then one or more Image File Directories (IFDs). The header is 8 bytes: II or MM to say whether numbers are little-endian (Intel) or big-endian (Motorola), the number 42, and the offset of the first directory. Each directory is a list of tags, and each directory can point to the next one. That chain is how a single TIFF holds several pages, and also how it tucks a small thumbnail next to the main image.
Offset 0 49 49 2A 00 "II", then 42: a little-endian TIFF
Offset 4 08 00 00 00 first directory starts at byte 8
Offset 8 IFD 0: ImageWidth, ImageLength, BitsPerSample,
Compression, PhotometricInterpretation,
StripOffsets, XResolution, ... , next IFD
IFD 1: page 2 (or a thumbnail), next IFD
...
The same structure is flexible enough that other formats borrow it. Canon CR2 and Adobe DNG camera RAW files open with exactly this header, which is why a converter has to read further into the file before deciding a .tif really is a plain TIFF.
Why are TIFF files so big?
TIFF files are big because they usually keep every pixel exactly, at full resolution, with either no compression or lossless compression. Nothing is thrown away, so the file size tracks the pixel count closely.
The arithmetic is short. A US Letter page scanned at 300 dpi is 2550 x 3300 pixels, which is 8.4 million pixels. At 8 bits for each of red, green and blue, that is three bytes per pixel, or about 25 MB before any compression. Scan the same page at 600 dpi and the pixel count quadruples to roughly 101 MB. Save it at 16 bits per channel, which many scanners offer for archival work, and it doubles again.
| Scan | Pixels | Color depth | Raw size |
|---|---|---|---|
| Letter page, 300 dpi, black and white | 2550 x 3300 | 1 bit | about 1 MB |
| Letter page, 300 dpi, grayscale | 2550 x 3300 | 8 bit | about 8.4 MB |
| Letter page, 300 dpi, color | 2550 x 3300 | 24 bit | about 25 MB |
| A4 page, 300 dpi, color | 2480 x 3508 | 24 bit | about 26 MB |
| Letter page, 600 dpi, color | 5100 x 6600 | 24 bit | about 101 MB |
| Letter page, 600 dpi, color, 16 bit per channel | 5100 x 6600 | 48 bit | about 202 MB |
Lossless compression narrows those numbers, but less than people expect for photographs and color scans. LZW and ZIP work by finding repeated patterns, and paper texture, film grain and sensor noise are close to random, so a color scan often shrinks by only a modest fraction. Lossy JPEG compression, by contrast, can cut the same image to a tenth of its size or less, because it discards detail the eye is unlikely to miss.
Two other things inflate TIFFs. Some files carry extra channels or layers saved by an editor, and some keep a CMYK version of the image for print, which is four channels instead of three.
What compression can a TIFF use?
A TIFF can use no compression, several lossless methods, or lossy JPEG, and the Compression tag (tag 259) records which. The choice explains most of the size difference between two TIFFs of the same picture.
| Code | Method | Lossless? | Typical use |
|---|---|---|---|
| 1 | None | Yes | Scanner defaults, maximum compatibility |
| 2, 3, 4 | CCITT modified Huffman, Group 3, Group 4 | Yes | Black-and-white fax and document scans |
| 5 | LZW | Yes | General-purpose, widely supported |
| 6, 7 | JPEG (old-style and current) | No | Photos where size matters |
| 8, 32946 | ZIP (Deflate) | Yes | General-purpose, often smaller than LZW |
| 32773 | PackBits | Yes | Simple run-length encoding, old Mac software |
| 34712 | JPEG 2000 | Either | Some archives and medical imaging |
The CCITT row deserves its own sentence. Group 4 is the coding scheme defined in ITU-T Recommendation T.6 for fax machines, and it only works on 1-bit images: every pixel is black or white. A page of typed text stored that way is tiny, often a few tens of kilobytes, because Group 4 describes each row mostly as changes from the row above it. That is why fax software and document management systems still produce TIFFs. No other widely supported format compresses a scanned letter better without losing anything.
Compression also explains a common failure. A reader that does not implement a method either refuses the file or, in some older software, silently draws a black rectangle. When you convert a TIFF to JPG on Toolz, the decoder reads uncompressed files and codes 2 through 8, PackBits and both ZIP variants. A file using anything else, such as JPEG 2000 inside a TIFF, is refused with the compression code named in the message, and the fix it suggests is to re-save the file with LZW, ZIP or no compression.
When should you still use TIFF?
Use TIFF when the file is a master copy you will edit, print or archive, and not when the file is meant to be looked at by someone else. The strengths that make it heavy are the same ones that make it the right choice for those jobs.
Archiving scans and digitized originals. A lossless TIFF is a faithful record that can be re-encoded to any future format without piling up compression damage. It supports 16 bits per channel, which keeps smooth tonal gradations in photographs and film scans. Libraries and archives favor it for exactly this reason.
Print production. Printers and prepress workflows accept TIFF because it can carry CMYK color, high resolution, an alpha channel for clipping, and a stated print resolution. A JPG can technically carry CMYK too, but plenty of print pipelines expect TIFF and will ask for it.
Fax and document systems. Fax servers, some e-discovery tools and older document management systems store pages as Group 4 TIFFs, often many pages per file. If a system hands you TIFFs, it usually expects TIFFs back.
Editing without generation loss. If an image will be opened, changed and saved many times, a lossless format avoids the slow smearing that repeated JPEG saves produce. TIFF and PNG both work for this. TIFF wins when you need 16-bit depth or CMYK, and PNG wins everywhere else.
And here is when TIFF is the wrong choice: emailing a scan, putting an image on a website, attaching a document to an upload form, or sharing a photo in a chat. Many browsers do not display TIFF at all, most phone galleries show a download prompt instead of a picture, and upload forms tend to list JPG, PNG and PDF only.
TIFF vs JPG vs PNG vs PDF: which should you convert to?
Pick the target by what is in the image and where it is going. Photos go to JPG, flat graphics and text go to PNG, and documents go to PDF.
| Target | Best for | Size vs uncompressed TIFF | What you lose |
|---|---|---|---|
| JPG | Photos, color scans, pages with pictures | Usually a small fraction | Some fine detail, 16-bit depth, transparency, extra pages |
| PNG | Black-and-white pages, line art, screenshots, logos, anything with transparency | Smaller for flat images, large for photos | 16-bit depth (in a browser conversion), CMYK, extra pages |
| Multi-page scans, e-filing, printing, one attachment for many pages | Depends on how pages are embedded | Very little if pages are stored losslessly | |
| Keep TIFF | Masters, print handoff, fax systems | Baseline | Nothing |
A photo scan converted to JPG at a high quality setting looks the same to almost everyone and takes a fraction of the space. A black-and-white contract converted to JPG is the classic mistake: JPG has no 1-bit mode, so the page becomes 8-bit grayscale, small speckles appear around letter edges at low quality, and the result can end up larger than the Group 4 TIFF it came from. For that kind of page, a PNG keeps the edges exact and compresses flat black and white well. The TIFF to PNG converter is the better tool there, and it also keeps an alpha channel as real transparency.
If you want to go beyond these three targets, the Image Converter reads TIFF too and can write WebP, GIF, ICO and SVG as well, which is handy when a TIFF logo needs to become a web image or an icon.
How do you shrink a TIFF file?
Shrink a TIFF by changing its encoding, reducing its pixels, or both. Converting a color scan from uncompressed TIFF to JPG does most of the work on its own; for anything still too big, reduce the resolution next.
Here is the order that wastes the least quality:
- Match the format to the content. Photos and color scans to JPG, text pages and graphics to PNG. This is the single biggest saving.
- Drop the resolution if it is higher than the use. A 600 dpi scan viewed on a screen or printed at home carries four times the pixels it needs. Halving each dimension keeps a quarter of the pixels and roughly a quarter of the size.
- Lower the JPG quality in steps. Start at 90%, try 75%, and zoom in on the finest detail before going lower. Text shows damage sooner than photos.
- Recompress the result. Once the image is a JPG, PNG or WebP, a compressor can squeeze it further or switch it to WebP.
For step 1, drop the files on the TIFF to JPG converter. The Quality slider runs from 10% to 100% and starts at 90%, and each result card shows the before and after sizes with a percentage badge, so you see the saving immediately. A batch downloads as one ZIP.
For step 2, the image resizer scales a converted JPG or PNG down to the pixel size you need.
For step 4, Image Compress re-encodes an image as JPEG, PNG or WebP at a quality you pick and previews the new size before you download. One limit to know: Image Compress opens files with your browser's own image decoder, and most browsers other than Safari cannot read TIFF, so convert the TIFF first and compress the JPG or PNG that comes out. It keeps the pixel dimensions as they are, which is why resizing comes before it in the list.
If you are shrinking to hit a specific cap, such as a 2 MB upload limit, the image compression guide goes deeper on how quality settings map to file size.
How do you handle multi-page TIFFs?
Convert a multi-page TIFF to PDF when you need every page kept together, and to JPG or PNG only when you need the first page as an image.
This trips people up because a multi-page TIFF looks like a single image in most viewers. Open a 12-page fax in a basic image viewer and you may see page one with nothing to suggest eleven more exist. Converters vary too: on Toolz, the JPG and PNG converters take only the first page and say so in a note under the result, with the page count, so nothing disappears silently.
The TIFF to PDF converter keeps them all. Each page of the TIFF becomes a PDF page in the order it is stored, up to 100 pages per file, and small thumbnail images some scanners store alongside the pages are skipped rather than turning up as extra pages. Add several TIFFs and they go into one PDF, file after file in the order shown, or tick One PDF per image to keep them separate. PDF itself is standardized as ISO 32000, and it is what e-filing portals, lenders and insurers usually want.
There is a size trade to understand here. TIFF is treated as a lossless source, so each page goes into the PDF as PNG, pixel for pixel. That keeps signatures and small print sharp, but a Group 4 fax page re-stored as PNG can be several times larger than it was, and a TIFF that used JPEG compression grows for the same reason. If the PDF is too large for the portal, two routes work:
- Run the finished PDF through Compress PDF.
- For a color scan that does not need lossless pages, convert each page to JPG first and then build the PDF with JPG to PDF, which embeds JPG pages as JPEG at 92% quality. The JPG converter takes only the first page of a TIFF, so this route works best when your scanning software saves one TIFF per page.
Page size matters for printing. A TIFF records its dpi, but a PDF page is measured in points, 72 to the inch, and the converter does not read the stored dpi. With Fit to image, one pixel becomes one point, so a 300 dpi letter scan comes out as a page about 35 by 46 inches. It looks fine in a viewer that fits to the window and prints badly. Choose US Letter or A4 to match the paper you scanned and the scan lands on the page at its original resolution.
What gets lost when you convert a TIFF?
Converting a TIFF in a browser keeps the picture and drops most of what surrounds it: extra bit depth, the print color model, the metadata and, depending on the target, the extra pages.
- Bit depth. A browser canvas holds 8 bits per channel, so a 16-bit TIFF becomes 8-bit in the JPG, PNG or PDF. On a screen this is rarely visible. For archival masters it is a reason to keep the original.
- CMYK color. Print TIFFs in CMYK are turned into screen RGB with a simple formula, without the file's embedded color profile, so saturated colors can shift. If exact color matters, export an RGB copy from the software that made the file.
- Metadata. EXIF fields, GPS coordinates, embedded color profiles and the stored dpi value are not copied, because the output is rebuilt from decoded pixels. Pixel dimensions stay the same.
- Transparency. JPG has none, so transparent areas are filled with white, and the note mentions it only when the image had transparent pixels. PNG and PDF keep the alpha channel.
- Pages. JPG and PNG get the first page only. PDF keeps them all.
None of this touches the original file. Keep the TIFF as the master and treat the converted copy as the version for sending.
Why won't my TIFF open or convert?
A TIFF that will not open is almost always one of four things: an unsupported compression method, a size limit, a damaged file, or a file that is not a plain TIFF at all.
| Symptom | Likely cause | Fix |
|---|---|---|
| Browser shows a download prompt | The browser has no TIFF decoder (most besides Safari) | Convert to JPG, PNG or PDF |
| Message naming a compression code | JPEG 2000, LZMA, Zstandard or another method the decoder lacks | Re-save with LZW, ZIP or no compression |
| Black or blank image in older software | Same as above, in a reader that fails silently | Re-save, or use a converter that reports the code |
| "Larger than 100 megapixels" | Very high-dpi or panoramic scan | Downsample in the scanner or an editor first |
| "Files over 300 MB are refused" | Uncompressed 16-bit or 600+ dpi scan | Re-save with ZIP compression, or reduce dpi |
| Only one page shows up | Multi-page TIFF opened as an image | Convert to PDF to see every page |
| Pointed to a RAW converter | The file is a CR2 or DNG with a .tif look-alike structure |
Use the CR2 or DNG converter |
The size limits exist to protect the browser tab. A decoder working client-side holds the file and a copy of its pixels in memory, and a 100-megapixel RGBA image alone takes 400 MB. Refusing the file with a clear message beats freezing the page.
The last row is worth explaining. Converters on Toolz identify files by their first bytes rather than by the extension, and because CR2 and DNG share the TIFF header, the decoder reads further to check for their markers. A camera RAW file sent to a TIFF page is recognized and pointed to the right place. Why RAW files need different handling is covered in the camera RAW guide.
Is it safe to convert scanned documents online?
It is safe when the conversion is client-side, meaning your browser decodes and re-encodes the file and nothing is uploaded. That matters for TIFFs more than most formats, because they are so often scans of contracts, medical forms, tax records and IDs.
On the Toolz TIFF converters, the decoder script (UTIF, an open source TIFF reader) downloads the first time you convert a file, and after that your browser does all the work. The image never leaves your device. The only network traffic is a daily limit check and a count of converted files and bytes, with no file names or page content. Converted files stay in the tab's memory until you remove them or close the page.
A server-based converter is not automatically unsafe, but you are trusting its retention policy with a copy of the document. A client-side tool removes the question.
Frequently asked questions
What is a TIFF file used for?
A TIFF file is used for archive-quality scans, print production and fax or document systems, where keeping every pixel exactly matters more than file size. It is a poor choice for email, websites and phones, which often cannot display it.
Is TIF the same as TIFF?
Yes. .tif and .tiff are two extensions for the same Tagged Image File Format. The shorter one dates from old filename length limits.
Why is my TIFF file so large?
TIFFs usually store every pixel uncompressed or with lossless compression. A letter-size color page at 300 dpi holds about 25 MB of raw pixel data, and 600 dpi or 16-bit scans are several times larger.
How do I reduce the size of a TIFF file?
Convert it to a format suited to its content: JPG for photos and color scans, PNG for black-and-white pages and graphics. Then lower the resolution if it exceeds what you need, and lower JPG quality in small steps while checking fine detail.
Should I convert a scanned document TIFF to JPG or PNG?
Use PNG for black-and-white or text-heavy pages, because it keeps letter edges exact and JPG can come out larger than a fax-compressed TIFF. Use JPG for color scans and pages with photographs.
How do I convert a multi-page TIFF without losing pages?
Convert it to PDF. Each page of the TIFF becomes a page of the PDF in order, whereas JPG and PNG conversions take only the first page.
Does converting TIFF to JPG lose quality?
Some, because JPG is lossy and stores 8 bits per channel. At a quality setting around 90% the difference is hard to see on photos and color scans; convert to PNG if every pixel must be kept.
Can I convert TIFF files without uploading them?
Yes. The Toolz TIFF to JPG, TIFF to PNG and TIFF to PDF converters decode and encode client-side in your browser, so the files never leave your device.
