How Many Hours Are in a Day, Week, Month, and Year?

"How many hours are in a year?" sounds like it should have one clean answer, and for a day or a week, it does. But the moment a month or a year enters the picture, the answer starts depending on which month, and whether it's a leap year — and treating every month as an equal chunk of hours is exactly where staffing plans, subscription billing, and leave-accrual spreadsheets quietly go wrong.

This page lays out the fixed numbers, the ones that vary, and why — plus the single approximate figure worth knowing if you need to annualize something without picking a specific month. If you're after a specific calculation involving hours worked or overtime, the hours calculator handles that directly.

A day is 24 hours. That's the definition a calendar day is built on: one full rotation of the Earth, divided into 24 equal hours, and it's the basis for every other figure on this page.

There's exactly one everyday exception: the two days a year when clocks shift for daylight saving time. The day clocks "spring forward" is 23 hours long, and the day they "fall back" is 25 hours long — the clock skips or repeats an hour, but the planet still turns once. It's a minor wrinkle for most people, but a real one for payroll systems that log a shift by clock time rather than elapsed time. The full mechanics are covered in what daylight saving time is and how it works.

A week is 168 hours: 7 days × 24 hours. Unlike a month or a year, a week's length in hours never changes — even a week that contains a daylight-saving switch still totals 168 hours across the wider Gregorian calendar's design, since the missing or repeated hour is a display quirk of clock time, not a change in how many hours actually pass.

This is where "a month" stops being one number. The Gregorian calendar splits the year into 12 months of unequal length — 28, 29, 30, or 31 days — so the hour count follows the day count directly: multiply the days in that specific month by 24.

• 28-day February (a common year): 28 × 24 = 672 hours — the shortest month.
• 29-day February (a leap year): 29 × 24 = 696 hours.
• 30-day months (April, June, September, November): 30 × 24 = 720 hours.
• 31-day months (January, March, May, July, August, October, December): 31 × 24 = 744 hours — the longest.

That's a spread of 72 hours — three full days — between the shortest and longest month. A staffing or billing model that assumes every month is the same length can be off by that much before anything else even goes wrong.

Every month in a common year, its day count, and its hour total. The two February rows show both the common-year and leap-year figures.

Add the twelve common-year rows and the total is exactly 8,760 hours; swap in the leap-year February and it's 8,784 — both figures match the year totals in the next section, which is a useful way to check the math by hand.

A year's hour total comes straight from its day count:

• Common year (365 days): 365 × 24 = 8,760 hours.
• Leap year (366 days): 366 × 24 = 8,784 hours — 24 hours more, the entire extra day of February 29.

A year is a leap year if it's divisible by 4 — except century years, which are only leap years if they're also divisible by 400. That's why 2024 and 2028 are leap years, 1900 was not, but 2000 was. Under that rule, leap years land roughly every four years, with three skipped per four centuries, giving the Gregorian calendar an average year length close to 365.2425 days rather than exactly 365.25.

Sometimes you need a single hours-per-month figure that isn't tied to a specific calendar month — annualizing a rate, or estimating a recurring cost. For that, the useful number is an average, built from the calendar's average year length rather than any one month's actual length.

Using 365.25 days as the average year (the simple leap-year approximation, before the small century-year correction): 365.25 × 24 = 8,766 average hours per year, divided by 12 months gives 730.5 average hours per month. This is a widely used approximation — subscription and cloud-hosting billing systems commonly use a flat figure close to 730 hours as a standard billing month rather than counting each customer's actual calendar days.

The important caveat: 730.5 is not the hour count of any real month — the closest real months are 720 (30-day) and 744 (31-day) hours, and no calendar month lands on 730.5. Use it only where an approximation is genuinely appropriate, not as a substitute for the actual figure in the chart above.

• Subscription and cloud billing: usage-based pricing (compute hours, per-seat licensing) often bills against a flat monthly hour figure rather than the customer's actual calendar month.
• Leave and PTO accrual: annual leave hours are usually calculated against the true 8,760 or 8,784-hour year, not an average, since employees need the exact figure for their specific year.
• Staffing and shift planning: a rota built on "4 weeks = a month" quietly loses 2–3 days a year compared with the real calendar, since most months run longer than 28 days.
• Payroll: converting an annual salary to an hourly rate needs the real year total, not the 730.5-hour approximation — see how to calculate hours worked for the method.

Enter a year to see whether it's a leap year and its total hours.

• Assuming every month has the same number of hours — the true range is 672 to 744, a 72-hour spread.
• Using "4 weeks" as a stand-in for "1 month." Four weeks is 672 hours; most months run longer, so this consistently undercounts.
• Applying the 730.5-hour average to a specific calendar month's actual total, rather than to a genuinely approximate calculation.
• Forgetting the leap-year rule's century exception — assuming any year divisible by 4 is automatically a leap year misses that 1900 was not (though 2000 was).
• Ignoring the 23/25-hour daylight-saving days when a calculation depends on elapsed clock hours rather than calendar days.