Does Week of Month upload my file or text to Tool-You servers?

No. Week of Month runs in this browser tab. Files stay on the device. Limit note: Local calendar. Weeks counted as ceil(lastDay/7).

Should I use ISO Week Number instead of Week of Month?

Use Week of Month when you need Week-of-month plus how many weeks the month has. Use ISO Week Number when you need ISO-8601 week and ISO year. They share a category (Date & time) but not the same job.

Week of Month

Week-of-month plus how many weeks the month has.

Ceil(day/7) week index, day of month, and how many such weeks the month contains. Unlike ISO Week this is not week-of-year. Invalid dates fail.

What Week of Month does

Ceil(day/7) week index, day of month, and how many such weeks the month contains. Unlike ISO Week this is not week-of-year. Invalid dates fail.

The interactive controls for Week of Month load after this article so crawlers still read the instructions. Path /datetime/week-of-month is the canonical address. Work happens on this device; Tool-You does not take a copy of the file or pasted text for Week of Month.

How to use Week of Month

Confirm you need Week of Month, not ISO Week Number (ISO-8601 week and ISO year.). Address: /datetime/week-of-month.
Enter the numbers or dates Week of Month uses. Week-of-month plus how many weeks the month has.
Read the result as Week of Month defines it — not as Day of Year (Ordinal day 1–366 plus remaining days in the year.). Ceil(day/7) week index, day of month, and how many such weeks the month contains. Unlike ISO Week this is not week-of-year. Invalid dates fail.
Week of Month is an estimate in the browser, not professional advice. Local calendar. Weeks counted as ceil(lastDay/7).
Need a different formula? Try Day of Year (Ordinal day 1–366 plus remaining days in the year.) instead of stretching Week of Month.

When not to use Week of Month

Skip Week of Month when a neighbor tool matches better — start with ISO Week Number or Day of Year — or when the description already warns the job will fail. In the tool’s own words: Ceil(day/7) week index, day of month, and how many such weeks the month contains. Unlike ISO Week this is not week-of-year. Invalid dates fail.

Questions about Week of Month

What does Week of Month do that other Date & time pages on this site do not?: Ceil(day/7) week index, day of month, and how many such weeks the month contains. Unlike ISO Week this is not week-of-year. Invalid dates fail. Short version: Week-of-month plus how many weeks the month has.
Does Week of Month upload my file or text to Tool-You servers?: No. Week of Month runs in this browser tab. Files stay on the device. Limit note: Local calendar. Weeks counted as ceil(lastDay/7).
Should I use ISO Week Number instead of Week of Month?: Use Week of Month when you need Week-of-month plus how many weeks the month has. Use ISO Week Number when you need ISO-8601 week and ISO year. They share a category (Date & time) but not the same job.
What are the limits of Week of Month?: Local calendar. Weeks counted as ceil(lastDay/7). Also: Ceil(day/7) week index, day of month, and how many such weeks the month contains. Unlike ISO Week this is not week-of-year. Invalid dates fail.