Description
Advance an ISO weekday by a signed day offset with week carry.
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.
Advance an ISO weekday by a signed day offset with week carry.
When to use this tool
Use ISO Weekday Cycle Offset when checking the stated weekday or Gregorian calendar convention.
How to use the tool and how it works
- Enter weekday, dayOffset. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read weekday, weekCarry. Use the output convention below.
Advance an ISO weekday by a signed day offset with week carry. Require weekday 1-7; exact integer floor division by seven yields nonnegative remainder, returned weekday and signed weekCarry.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| weekday | Weekday | Required. Safe integer; minimum 1; maximum 7. |
| dayOffset | Day Offset | Required. Safe integer. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| weekday | Weekday | Required. Safe integer. |
| weekCarry | Week Carry | Required. Safe integer. |
{
"input": {
"weekday": 7,
"dayOffset": 2
},
"output": {
"weekday": 2,
"weekCarry": 1
}
}Limitations and assumptions
- Week carry is relative to the supplied weekday cycle, not an ISO week-year calculation.
- 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
- ISO Weekday Sunday Zero Crosswalk
Convert between ISO weekday numbering and Sunday-zero numbering.
- Date: Weekday Mask Bitset Label
Decode a seven-bit weekday mask to labels.