Dates
Days in a Month
Find out how many days are in any month, in any year.
Days in a Month
31 days
in July 2026.
The familiar "30 days hath September" pattern traces back to the Roman calendar reforms of 46 BC, with February left as the odd one out — and the popular story that Emperor Augustus later stole a day from February to lengthen August to match Julius Caesar's July is widely repeated folklore that historians actually treat as unsettled, not a confirmed fact.
It's a small fact with an outsized number of real applications: subscription billing that prorates a partial month, vacation-day accrual calculations, and even some recipe or industrial-process scaling calculations that assume a specific month length can all be thrown off by an unexamined assumption about how many days a given month actually has.
How the Days in a Month works
Every month except February has a fixed day count regardless of year: 31 days in January, March, May, July, August, October, and December; 30 in April, June, September, and November. February alone depends on whether the selected year is a leap year, using the exact same rule as the Leap Year Checker, so the two tools always agree.
Payroll, billing, and rent-proration systems frequently need to know a specific month's exact day count to correctly calculate a partial-month, per-day rate — a genuinely practical use for a fact that otherwise mostly shows up as a memorized childhood rhyme.
Worked example
February 2026 has 28 days, since 2026 isn't a leap year. February 2028 has 29 days, since 2028 is divisible by 4 and isn't a skipped century year.
Edge cases this tool handles correctly
- February is the only variable month
- Every other month's length is fixed no matter which year is selected — February is the sole exception, and its length is derived from the Leap Year Checker's rule, not a separate assumption.
- The Augustus legend is disputed
- The popular story that August was lengthened to 31 days (taking a day from February) specifically to match Julius Caesar's July is widely repeated but genuinely disputed among historians of the Roman calendar — this tool states that honestly rather than presenting it as settled fact.
- Checking a month across many different years
- Every month's length is fixed except February's, so re-checking January, March, or any other non-February month across several different years always returns the same number — only February's answer changes depending on the year selected.
- Checking multiple months at once
- The tool answers one month/year combination at a time; comparing several months means checking them individually, since there's no single meaningful "total" that would make sense across differently-named months.
- The 30/31 pattern isn't perfectly alternating
- "30 days hath September, April, June, and November" is the traditional memory rhyme, but the 30-vs-31 pattern doesn't alternate cleanly through the whole calendar — July and August are both 31-day months back to back, which is exactly the detail the Augustus legend is commonly invoked to explain, disputed as that explanation actually is.
Frequently asked questions
Why does February have fewer days than every other month?
See the intro above — the honest short answer is that the full history is genuinely disputed among historians, particularly the popular Augustus legend.
Why are July and August both 31 days in a row, breaking the alternating pattern?
That back-to-back pair is exactly the anomaly the popular (but disputed) Augustus legend is invoked to explain — historians don't treat that story as settled fact, but the irregularity itself is real and visible in the modern calendar.
Which months always have 30 days regardless of the year?
April, June, September, and November are always 30 days in every year — unlike February, none of them are ever affected by the leap-year rule.
Does this tool know about leap years automatically?
Yes — see the how-it-works section above for exactly how February's count is derived.
Can I check a whole year's total at once?
Yes — see the Days in a Year tool for the full-year total rather than a single month.
Are any other months' lengths affected by the year?
No — only February's length depends on the specific year; every other month is fixed.
Does checking the same non-February month in different years change the answer?
No — every month except February has a fixed length regardless of year; only February's day count depends on the specific year.
Is this the same information as a paper calendar?
Yes — it's the same day counts you'd find on any printed calendar, just computed directly rather than looked up, and automatically correct for February in any given year.