All limits at a glance
The table shows which limit applies to which tool and whether it is checked on input or on output. Each row is a separate condition. A file must therefore meet all limits that apply to the chosen tool. The information is current as of 14 October 2026.
File and operation limits
How large may a single file be?
Every PDF, JPG or PNG file you select in a tool may be at most 50 MiB. That is exactly 52,428,800 bytes, and this value itself is still allowed. From 52,428,801 bytes, the file is rejected. For a DOCX file in Word to PDF, the limit is 20 MiB, i.e. exactly 20,971,520 bytes; from 20,971,521 bytes, it is rejected. The 100 MiB limits further down do not allow a larger single file: they limit either the sum of several selected files or the output of a tool, which depending on the tool is a single new PDF or all output files together.
MiB is not the same as MB
MiB is a binary unit: 1 MiB is 1,048,576 bytes. One MB in the decimal sense is 1,000,000 bytes. 50 MiB therefore corresponds to about 52.43 MB. File managers and portals calculate differently, and some displays label binary values as MB anyway. If your file is close to the limit, the rounding of a display alone can tip the balance. In that case, only the exact byte count in the file properties is reliable. With the converter, you can distinguish MB and MiB.
What does the per-operation limit mean?
When merging and in Images to PDF, you select several files at once. Two conditions must then be met at the same time: each individual file is at most 50 MiB, and all files together are at most 100 MiB, i.e. 104,857,600 bytes. If your selection meets only one of the two conditions, it is rejected.
Input and output are checked separately
Outputs have their own limits, also of 100 MiB. This concerns the new PDF when merging, deleting pages, rotating and in Images to PDF, as well as the sum of all split PDFs when splitting and the sum of all page images when exporting as JPG or PNG. Input and output are not added together into a shared budget. If you merge two files totaling 80 MiB, the 80 MiB are checked against the input limit, and the new PDF is checked separately against the output limit.
If a tool produces several output files, for example when splitting or exporting images, you can additionally save them as a ZIP archive. The archive needs additional memory and can fail even though the individual files are finished. They then remain available to save individually. Incidentally, a ZIP archive is not a smaller PDF, just a package of several files.
Compress: one file of at most 50 MiB
The compressor always processes exactly one file of at most 50 MiB. It delivers a smaller output or leaves the file unchanged if no reduction succeeds. It never produces a larger file. However, a specific target size is not guaranteed. How to set a limit and what helps if it is missed is explained under Compress PDF to a target size.
Page and pixel limits
250 pages per operation
Merging, splitting, deleting pages, rotating and exporting as JPG or PNG process at most 250 pages per operation. The entire source document is counted, before you select pages. So from a PDF with 300 pages, you cannot export or delete even just ten pages. When merging, the pages of all input PDFs count together, even if the individual documents are short. For longer documents, the page tools currently offer no workaround.
The number 250 also limits files: when merging, at most 250 input files are possible, when splitting at most 250 output files, and in Images to PDF at most 250 images, i.e. 250 pages. The compressor has no 250-page limit. For the compressor, what counts is the file size, memory and the type of document.
Pixel area is not file size
For images, the pixel area, i.e. width times height, counts in addition to the bytes. A JPG or PNG for Images to PDF may have at most 40,000,000 pixels. The original image is checked before it is decoded or downscaled. This applies to the Original format setting just as it does to JPEG downscaling to a longest edge. An image that is too large therefore cannot be rescued via the downscaling option.
Heavily compressed photos or simple graphics can be only a few MB in size and still have too many pixels. Conversely, a passed pixel check says nothing about whether the image file is valid or whether your device can decode it.
16 million pixels per exported page
When exporting a PDF as JPG or PNG, each rendered page may be at most 16,000,000 pixels. This limit applies per page, not to all images together. The 100 MiB limit applies to the total size of all images. How many pixels a page gets depends on its format and the selected resolution: 96, 150, 200 or 300 DPI. The default is JPG at 150 DPI and 90 % quality.
If a page is too large, a lower resolution helps. Selecting fewer pages reduces the total size of the images but does not get around the 250-page limit of the source document. For other formats, you can use the DPI calculator to calculate the pixel dimensions of a page.
Calculators and file inspection
The calculators for file size, DPI, compression ratio, upload time and email attachments work only with numbers you enter. They do not open any file, so no 50 MiB limit applies to them.
The upload limit calculator is a special case. There you can select PDFs from your device, and it records their actual file size in bytes, even for PDFs above 50 MiB. For PDFs up to 50 MiB, it also tries to read the page count without modifying the file. Above 50 MiB, it skips this step, and the page count can also remain unknown for protected or unreadable PDFs. It still checks the size and number of files. In these cases, it can only evaluate a page requirement if you enter the page count yourself.
The fact that the calculator records an 80 MiB PDF does not mean that the PDF tools will accept it. It compresses nothing and lifts no limit. You enter the recipient's requirements yourself as rules. A passed result shows that your files meet these rules, but it is no guarantee that a portal will accept them. To compare against a recipient's limit, you can check the upload limit.
Supported documents
Why a small file can still be rejected
Size is only one of several conditions. In all PDF tools, even a file well below 50 MiB is rejected if one of these cases applies:
- It is damaged, empty or not a valid PDF.
- It is encrypted or password-protected. That is different from a damaged file: it can be opened with the password, but the tools do not process it.
- It carries a digital signature or is certified. An inserted image of your signature does not count, because it is ordinary page content.
Additional rules for page tools
Merging, splitting, deleting pages and rotating copy pages into a new PDF; exporting as JPG or PNG draws pages as images. Before they start, these five tools additionally reject PDFs that have any of the following features:
- interactive forms, including XFA forms
- portfolios or embedded files
- optional layers
Forms in the compressor
The compressor checks differently. It does not reject ordinary forms without a digital signature as a matter of principle. Its automatic checks concern the structure and the page count of the output. Whether form fields are still fillable afterwards and work as expected is something you check yourself in the saved copy. A tool accepting a file does not prove that every feature is preserved. You can find more in the guide on signatures and forms when compressing.
What is carried over and what leads to rejection
The conversions between PDF and Word and text recognition have their own content rules, independent of those of the compressor and the page tools:
- PDF to Word requires an unprotected PDF with usable text. Forms, embedded files, optional layers, and rotated or not clearly readable text or structure lead to rejection. Pages that consist only of a scan need text recognition first.
- Text recognition accepts only PDFs, not JPG or PNG files. It recognizes pages that consist only of a scanned image and leaves pure text pages unchanged. Both kinds may occur in the same document. A page with both text and an image is rejected, even if the image is only a logo.
- Word to PDF accepts only unprotected DOCX files, not older DOC files. Files with comments, track changes, hidden text, macros, fields, footnotes, signature markers in the file package, or complex layout, complex images or tables are rejected.
Here too, the acceptance of a file does not prove that the output matches the original. PDF to Word and Word to PDF reflow the text and do not carry over an exact page layout, Word to PDF replaces all fonts with Liberation Sans, and text recognition is not guaranteed to be error-free. PDF/A or PDF/UA conformance is not promised. You should therefore check the saved file.
Browser and practical limits
A file within all limits will not necessarily go through on every device. Processing takes place in your browser. Memory, image decoders, the startup of the processing components and other system resources can therefore stop an operation even below the fixed limits. Local processing therefore does not mean that files, pages or pixels are unlimited. The fixed limits always apply, and your device's memory can additionally hold things back earlier.
If an operation aborts
- Close other tabs and programs that use a lot of memory, and start the operation again.
- When exporting images, choose a lower resolution or fewer pages.
- Save several output files individually instead of as a ZIP archive.
- Process large files on a computer rather than on a smartphone.
- Save finished outputs before you leave the page or click “Edit a new file”.
What stays in the browser and what is loaded over the network is explained on the page Processing and technical limits.
Current access and costs
As of 13 October 2026, you need neither a sign-in nor an account for the existing tools. There is no payment step, no paywall and no daily limit on the number of your operations. The tools also do not add a watermark to your outputs.