Description
Convert a supplied modulo-11 remainder into an ISSN-style check digit or X.
Identifier validation can involve several distinct questions: whether text has the expected shape, whether a checksum is consistent, and whether an authority actually assigned the identifier. Formatting and field extraction address narrower questions. Each result must be read according to the particular property the tool checks.
Convert a supplied modulo-11 remainder into an ISSN-style check digit or X.
When to use this tool
Use ISSN Numeric To X Check Symbol when you need the particular shape, formatting, field, or checksum property as one explicit stage in an identifier workflow.
How to use the tool and how it works
- Enter remainder. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read symbol. Use the output convention below.
Require integer remainder from zero through ten. Calculate check=(11-remainder)%11 and return X for ten or the decimal digit otherwise.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| remainder | Remainder | Required. Safe integer; minimum 0; maximum 10. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| symbol | Symbol | Required. Text; maximum UTF-16 length 8192. |
{
"input": {
"remainder": 1
},
"output": {
"symbol": "X"
}
}Limitations and assumptions
- Remainder must already come from the intended weighted checksum body. The tool does not compute that weighted sum, validate a full ISSN, or verify registry assignment.
- The field tables state structural bounds; the mechanics also specify cross-field constraints. Malformed inputs and unsupported domains cause errors. A successful false flag, empty branch value, or zero placeholder has the meaning stated above and is distinct from an input error.
Alternative or Complementary methods
Use a complete format and checksum validator when required, then consult the issuing registry or verification process for assignment and identity. Preserve meaningful leading zeros as text.
References
Similar or alternative tools
- ISSN X To Ten Value
Map one ISSN-style digit or uppercase X check symbol to its numeric value.
- ISNI Final Check Symbol Case
Normalize the single lowercase token x to X and otherwise preserve symbol.