Description
Return a serial month coordinate.
Civil calendar arithmetic needs explicit year numbering, leap rules and index origins. A weekday mask or Gregorian component operation does not identify a timezone, working calendar or historical calendar reform.
Return a serial month coordinate.
When to use this tool
Use Calendar Month Ordinal Serial Pair when checking the stated weekday or Gregorian calendar convention.
How to use the tool and how it works
- Enter year, month. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read serial. Use the output convention below.
Return a serial month coordinate. Require month 1-12; serial = year*12+month-1.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| year | Year | Required. Safe integer. |
| month | Month | Required. Safe integer; minimum 1; maximum 12. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| serial | Serial | Required. Safe integer. |
json
{
"input": {
"year": 2026,
"month": 10
},
"output": {
"serial": 24321
}
}Limitations and assumptions
- January of year zero has serial zero; a supplied integer-year coordinate is not a timestamp or elapsed-day count.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use an appropriate full calendar library and authoritative local rules when business days, historical dates or real scheduling matter.
References
Similar or alternative tools
- Date: Calendar Month Length With Leap Flag
Return month length under a supplied leap-year flag.
- Calendar Month End Subtraction Clamp Loss
Clamp a source day to a supplied target-month length.