A file's name is the first thing you see when you look for something, and it is often the only information that survives when the document is sent by email, copied to a USB stick or uploaded to a portal. «Scan0012.pdf» and «Document1.docx» say nothing. A well-built name, on the other hand, lets you understand the content without opening the file and sort it correctly in any folder.
What a name should say
A good name answers three questions, in the order most useful to you:
- When: the date of the document, not the date you saved it.
- What: the type of document (invoice, contract, minutes, quote).
- Whose or about what: the other party, the project, the subject.
An example: 2025-03-14_invoice_plumber-rossi.pdf. Reading it you immediately know what it is, and placed next to other invoices it sorts chronologically.
Characters to avoid
Different systems handle characters differently. A name that works perfectly on your computer can cause problems on another operating system, in a cloud service or in a web address. It is best to avoid:
- Spaces: they are not forbidden, but in many contexts they become
%20or cause trouble in scripts. Hyphens or underscores are better. - Slashes and colons (
/ \ :): they are path separators on some systems and can make a file impossible to copy. - Asterisks, question marks, quotation marks, the symbols
< > |: they are forbidden on Windows and cause sync errors. - Accented letters and emoji: they usually work, but with some older programs, compressed archives or servers they turn into garbled characters.
- Dots in the middle of the name:
report.final.v2.docxcan confuse readers about the real extension.
A simple rule is to use only unaccented letters, numbers, hyphens and underscores.
Separators: consistent use
A scheme I find very readable uses two separators with distinct roles:
- the underscore
_separates blocks of information (date, type, subject); - the hyphen
-joins words within the same block.
So 2025-03-14_quote_bathroom-renovation.pdf reads as three blocks: date, type, a two-word subject. Consistency matters more than the specific choice: what counts is always using the same pattern.
Upper and lower case
Some systems treat Invoice.pdf and invoice.pdf as different files, others do not. Mixing upper and lower case at random leads to duplicates that are hard to spot. The most robust solution is to write everything in lower case; alternatively you can use capitals only for acronyms and proper names, but always in the same way.
Length
A name should be descriptive, not a summary. Beyond forty or fifty characters it becomes hard to read in dialog windows, and very long paths can exceed the limits of some programs on Windows. If you feel the need to write a whole sentence, you are probably putting into the name information that belongs to the folder. There is no need to write 2025_finances_bank_statement_march if the file is already in Finances/Bank/Statements.
Numbers and sorting
If you have a series of numbered files, always use the same number of digits. The computer sorts chapter-10 before chapter-2 because it compares characters one by one. With chapter-02 and chapter-10 the order is correct. If you expect more than 99 items, start with three digits: 001, 002.
A shared convention
Naming rules become truly useful when the whole group follows them: a family sharing documents, a small office, a project team. A few written lines are enough, for example:
| Element | Rule | Example |
|---|---|---|
| Date | YYYY-MM-DD at the start | 2025-06-01 |
| Type | fixed word from a list | invoice, contract, minutes |
| Subject | words joined by hyphens | paper-supply |
| Version | only if needed, v01, v02 |
v03 |
| Characters | lower case, no spaces or accents |
A closed list of document types (ten or fifteen words at most) prevents the same concept from being written as «inv», «invoice», «bill» and «fattura».
Renaming what comes from outside
Downloaded files, scans and attachments arrive with names chosen by someone else. The best moment to rename them is when you move them from the incoming folder to their final location: at that point you are already looking at them and know what they contain. Renaming months later means opening every file to remember what it is. If there are many files following a predictable pattern, bulk renaming with a dedicated tool or a small script saves a lot of time.
In short
- A useful name says when, what and about what, in that order.
- Use only unaccented letters, numbers, hyphens and underscores.
- Give each separator a precise role and always stick to it.
- Use leading zeros in numbered series for correct sorting.
- Write the convention down in a few lines and share it with the people you work with.
