The moment you hit Send or Upload is the wrong time to discover the file is too large, in the wrong format, or still contains a draft watermark. A quick preflight check costs thirty seconds and saves the back-and-forth of failed uploads and resent emails. This checklist is organised by destination so you only check what is relevant to where the file is going.
Before sending any file: universal checks
These apply regardless of whether you are emailing, uploading to a portal, or sharing via messaging.
- Is this the final version? Open the file and confirm you are looking at the right content, the correct date, and the right recipient name if personalised. Sending the wrong version of a contract, CV, or application is a common and avoidable error.
- Does the file open cleanly? Open it on a different device if possible, or at minimum close it and reopen it. A file that appears fine in the editor you used to create it can fail to open on another platform if the format has compatibility issues.
- Is the file name appropriate? Many portals reject files with spaces, special characters, or very long names. Use underscores instead of spaces and keep the name descriptive but concise. A name like "Ahmad_CV_2026.pdf" is better than "My CV (final version v3 updated).pdf".
- Is the format correct? If the recipient or portal expects a PDF, confirm the file is actually a PDF and not a DOCX or PPTX accidentally saved with a PDF extension. If images are expected as JPEG, confirm they are not PNG files renamed.
Email attachment checklist
Email attachment limits vary by provider. Gmail allows 25MB, Outlook typically 20MB, though many corporate email servers set custom lower limits that you cannot know in advance. A safe target for any professional email attachment is under 5MB. For attachments going to a corporate recipient, under 3MB is better.
- Is the total attachment size across all files in the email under the safe limit?
- If the file is a PDF, was it exported directly from the source application rather than printed to PDF? Direct exports are smaller and preserve text as text.
- If the file contains images, were the images compressed before being embedded in the document?
- Is there a better way to share this file? If it is above 10MB, a link to a cloud storage location is more reliable than an attachment.
- Have you removed any tracked changes, comments, or personal metadata from Office documents before attaching them?
Portal upload checklist
Government portals, scholarship systems, and university application platforms are the strictest environment for file uploads. They often enforce size limits, format restrictions, page count limits, and PDF version compatibility simultaneously.
- What is the exact size limit for this upload field? Check the platform's instructions or help section rather than guessing. Limits vary from 1MB on some Italian university portals to 10MB on others.
- Is the file genuinely under the limit? Check the file size on your device, not in the application you used to create it. Some applications show a compressed preview size rather than the actual file size.
- Is the file free of password protection? Most portals reject encrypted PDFs because they cannot process the content.
- Is the file free of embedded scripts or forms? Some complex interactive PDFs are rejected by portal validators.
- For scanned documents: is the text readable at 100% zoom? If you scanned in colour when the original is black and white, converting to grayscale before uploading will produce a cleaner, smaller file.
- Is the page order correct? Use a PDF viewer to scroll through every page before uploading.
- If the portal allows multiple uploads: have you split the content appropriately so each upload is well within the limit rather than pushing one large file to the maximum?
WhatsApp and messaging checklist
WhatsApp allows up to 100MB for documents sent as files and 16MB for videos. In practice, files above 5MB are slow to send on typical mobile connections and many recipients are on limited data plans. A good practical target is under 3MB for documents you want people to actually open.
- Is the file small enough to open quickly on a phone with an average connection?
- If sharing a photo: have you considered whether the recipient needs the full resolution, or would a compressed version work just as well?
- If sharing a PDF for casual reading on a phone: is the text large enough to read on a small screen without zooming?
- Are you sending this as a document or as a photo? Sending as a document preserves quality. Sending as a photo causes WhatsApp to apply its own compression, which can make text blurry.
Formal submission checklist (legal, academic, professional)
Legal documents, academic submissions, and professional filings have the highest stakes when something goes wrong. This checklist is for those contexts.
- Is this the version that was approved by all necessary parties?
- Have you compared this version against the previous draft to confirm no unintended changes were introduced? Use a comparison tool if the document went through multiple revisions.
- Are all signatures, stamps, and official markings present and legible?
- Is the document numbered correctly? If the submission guidance specifies numbered pages, confirm the numbering is applied and starts at the right number.
- Have you removed or redacted any information that should not appear in the submitted version, such as personal identifiers, internal annotations, or pricing information from a tender document?
- Is a record of what you submitted being kept? Save a copy of the exact file you uploaded, ideally with a timestamp, so you have evidence of what was submitted if a dispute arises later.
When to split versus when to compress
Splitting and compressing are two different tools for the same problem. Compression reduces the quality of the content to make it smaller. Splitting preserves quality by dividing the content into smaller pieces.
Compress when the content can withstand some quality reduction without affecting its usefulness. A certificate scanned at 600 DPI can be compressed aggressively with no practical loss of readability. A legal contract with fine print or a financial statement with small numbers should be compressed lightly or split rather than compressed to the point where digits become ambiguous.
Split when the portal accepts multiple uploads, when the content naturally divides into sections, or when even light compression would affect readability. A 10-page application pack can be split into separate files for the CV, cover letter, transcript, and certificates, each uploaded to its own field.
A quick size reference by file type
These are realistic targets after proper preparation. If your file is significantly above these ranges, there is usually a specific fixable reason.
- A single text-only PDF page should be under 50KB. A 10-page text document should be under 500KB.
- A single scanned page in grayscale at 150 DPI should be between 50KB and 200KB depending on complexity.
- A JPEG photograph at 1200 pixels wide and 85 percent quality should be between 100KB and 400KB.
- A PNG screenshot at 1400 pixels wide should be between 100KB and 600KB depending on content complexity.
- A typical CV or one-page application form should be under 500KB. If it is above 2MB, something has gone wrong in how it was created.
After sending: confirming delivery
A file that appears to send successfully does not always arrive or get processed correctly. For important submissions, build a confirmation step into your process.
- For portals: take a screenshot of the confirmation page or email that the portal sends after a successful upload. If you later need to prove you submitted on time, this is your evidence.
- For email: if the recipient is expecting the file, a brief confirmation message asking them to confirm receipt takes ten seconds and saves significant stress if something went wrong in transit.
- For formal filings: check whether the system sends a reference number or receipt. Keep this on record alongside a copy of the submitted file.