Result
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Facts and limits of this method
| Default mode | Replaces every comma, including ones separating list items |
|---|---|
| "Digits only" mode | Converts a comma only when it sits directly between two digits |
| Typical use | Preparing European-formatted decimal numbers (3,14) for software expecting a dot (3.14) |
| List safety | In digits-only mode, "apples, pears" is left alone since a space follows the comma, not a digit |
| Plain integer lists | In digits-only mode, "1,2,3,4" written without spaces gets every comma converted |
| Counter | Reflects the number of replacements actually made under the selected mode |
When it misleads you
- With the default settings (digits only off), every comma in the text is replaced with a period — including commas that separate items in a list. Running this on "apples, pears, bananas" produces "apples. pears. bananas", which breaks the list; always turn on digits only before running this on anything other than pure decimal numbers.
- Even with digits only on, a comma directly between two digits and nothing else gets converted — a list of plain numbers written without spaces, like "1,2,3,4" (meant as four separate integers), would have every comma converted into a period, producing "1.2.3.4", which reads as one broken decimal number instead of four integers.
- Digits-only mode is safe for typical prose lists specifically because list items are usually followed by a space ("item one, item two") — the comma there isn't directly between two digits, so it's left alone. It isn't a general list-detector, though; it works because of the digit-adjacency pattern, not because the tool understands what a list is.
- A number using a comma as a thousands separator (the US/UK convention, e.g. "12,345") also matches the digit-comma-digit pattern in digits-only mode and gets converted to "12.345" — the opposite of what's intended, since that comma isn't a decimal separator at all.
How it is calculated
In the default mode, the tool matches every literal comma in the text and replaces it with a period, counting every occurrence.
In digits-only mode, it looks specifically for a digit, followed by a comma, followed by another digit, and replaces only the comma in that pattern — counting only these matches.
Everything else in the text — letters, other punctuation, spaces — is left exactly as it was.
The counter shown always reflects how many replacements were actually made under whichever mode is selected.
Questions and answers
Why would I need this?
To convert European-style decimal numbers like "3,14" into the dot format "3.14" that most spreadsheets, databases and programming languages expect.
Is it safe to run this on a comma-separated list?
Only with digits-only mode enabled, and only if the list items aren't touching digits directly on both sides of the comma — always check the result. With the default settings, every comma in a list gets converted and the list breaks.
Will it break a thousands separator like 12,345?
Yes, if digits-only mode is on — it matches the same digit-comma-digit pattern as a decimal separator, so "12,345" becomes "12.345".
How is this different from the dot-to-comma replacer?
That tool does the opposite conversion — it turns periods into commas, for going from dot-formatted decimal numbers to the European comma style.
Is my text sent anywhere?
No. Everything runs in your browser; the text is never transmitted.