Hours Calculator
Determine how many hours and minutes separate two moments by employing the calculators underneath. If you need a complete time‑card, head over to the Time Card Calculator.
Hours Between Two Dates
An hour traditionally represents a span of 60 minutes, with each minute consisting of 60 seconds, a unit defined precisely by science. A day comprises 24 such hours, and people usually read time via either a 12‑hour or a 24‑hour clock.
12-hour clock:
The 12‑hour system runs from 1 to 12. Many analog watches don’t show whether it’s morning or evening, whereas digital devices label times with “AM” (ante meridiem, before noon) and “PM” (post meridiem, after noon). By convention, 12 AM marks midnight and 12 PM marks noon; saying “12 midnight” or “12 noon” can clear up any confusion.
24-hour clock:
The 24‑hour clock uses numbers 0 through 23, where 00:00 stands for midnight and the day cycles from one midnight to the next. This format is the global standard and helps avoid the ambiguity of the 12‑hour system. Hours 0–11 correspond to the AM period, and 12–23 to the PM period of a 12‑hour clock. In several nations it’s known as military time, a convention adopted by armed forces and other organisations that require precise timing.
Hours in different time periods
| Description | Hours |
| Hours in a day | 24 |
| Hours in a week | 168 |
| Hours in a month | 672 for a 28-day month 696 for a 29-day month 720 for a 30-day month 744 for a 31-day month 730.5 on average |
| Hours in a year | 8,760 for a 365-day year 8,784 for a 366-day year 8,766 on average |
| Hours in a decade | 87,648 for a 2-leap-year decade 87,672 for a 3-leap-year decade 87,660 on average |
| Hours in a century | 876,600 |