Japan phone number normalizer

How to use it

Normalize Japanese-looking phone-number strings line by line into a digits-only domestic form or +81 international form. It is useful for cleaning inconsistent CSV or contact-list formatting before comparison or import.

1. Paste one phone number per line.
2. Choose domestic 09012345678 or international +819012345678 output.
3. Run the cleanup and review every line marked ⚠ Check against the source data.

Removed

hyphens, spaces, parentheses and other separators

Domestic

digits beginning with 0

+81

replaces the domestic leading 0 with +81

Warning

⚠ Check for lines outside a simple Japanese 10/11-digit shape

090-1234-5678 can become 09012345678 or +819012345678

This is formatting cleanup, not telephone-number verification. A line without a warning is not proof that the number is assigned, active or owned by the expected person.