How to Check File Upload Requirements for Online Forms
A rejected upload often means the file fails a specific rule, not that the file is broken.
Step-by-step guidance
Read the form’s instructions for permitted formats, maximum size and required image dimensions. A limit written in MB may use a different calculation from the KB value displayed by your computer. For images, note both width and height in pixels. Use the file requirement checker to compare your file against the rules before uploading.
Separate file type, dimensions, and size
Upload instructions often combine several different restrictions. The file type describes the encoding or format, such as JPEG, PNG, or PDF. Image dimensions describe width and height in pixels. File size describes the amount of storage the file occupies. Passing one rule does not imply passing the others.
For example, a JPEG may be the correct format but still exceed a 200 KB limit. An image may be under 200 KB but have the wrong aspect ratio. Read the entire requirement before making changes so you do not fix one issue while creating another.
Use the checker to diagnose the problem
Start with the file you intend to submit, then enter the allowed extensions or formats, size threshold, and required image dimensions from the receiving website. Compare the reported results against the original instructions. If a field is not specified by the receiving website, do not invent a requirement.
A local check can catch straightforward mismatches, but it cannot reproduce every validation rule used by an external service. A portal may inspect the internal file format, reject corrupted documents, require specific colour profiles, or enforce content rules that a general checker cannot verify.
Choose the right fix for each failure
For an oversized photo, reduce dimensions or compress it while keeping text and faces legible. For incorrect image dimensions, crop, resize, or pad according to the required aspect ratio. For a rejected format, convert using a tool that actually exports the permitted format.
Check the downloaded result again after every change. File conversion and compression can affect both size and appearance. If the website still rejects the file, compare its exact error message with the rules and confirm whether the form requires separate documents or additional information.
Important details and common mistakes
If the size is too large, compress the image or PDF. If the dimensions are wrong, crop or resize the image without stretching it. If the extension is not accepted, convert to a permitted format using a compatible tool. The checker cannot guarantee that an external website will accept the document, because websites may have additional content and validation rules.
Ready to put this into practice?
Open File Requirement Checker →Frequently asked questions
Can I use the original file again?
Yes. Keep the unedited original so you can prepare another version if the requirements change.
How do I know the result is suitable?
Check the downloaded file against the destination requirements, including its appearance, dimensions, format, and size.
Will changing the file extension fix the problem?
No. A file extension is not a substitute for genuine conversion or editing. Use the appropriate tool and verify the output.