Counting Down a Notice Period: 30, 60, or 90 Days From Today

Why 'about a month' isn't precise enough

A calendar month is 28 to 31 days depending on which month it is — 'give one month's notice' and 'give 30 days' notice' aren't always the same end date. A notice given on January 31 and counted as 'one calendar month' could land on February 28, but 30 exact days lands on March 2 — a real 2-day difference that matters when a lease or contract specifies days, not months.

Whenever the actual document says a number of days rather than 'a month' or 'a pay period,' counting real calendar days from the notice date is the only way to land on the legally correct end date.

Calendar days vs. business days

Most notice periods (leases, resignations, many contracts) count calendar days, including weekends — a 30-day notice period given on a Friday still ends 30 calendar days later, regardless of how many weekends fall inside that span. A minority of contracts specify business days explicitly, which is a meaningfully longer real-world span since it skips weekends (and sometimes holidays) entirely — the document's exact wording determines which counting method applies.

When in doubt, the safest read is calendar days unless the text explicitly says 'business days' or 'working days' — getting this wrong in either direction can mean giving notice too late (if you assumed business days but calendar days were meant) or leaving unnecessarily early (the reverse).

Working backward from a target end date

The same calculation runs equally well in reverse: if you know exactly when you need a lease or job to end, count backward the required number of days to find the latest date you can give notice. This is the more common real-world question — 'by what date do I need to tell them' — and it's the identical day-counting math, just solved for the starting date instead of the ending one.