A time converter changes a duration from one unit into another — hours to minutes, days to hours, or seconds to weeks. It is useful for project planning, calculating billable hours, reading timeouts and durations in software, and answering the everyday "how many days is that?" questions. This tool covers milliseconds, seconds, minutes, hours, days, weeks, months and years.
The formula. Every value passes through one base unit, the second. The factors are 1 minute = 60 s, 1 hour = 3,600 s, 1 day = 86,400 s and 1 week = 604,800 s. Months and years need care: a calendar month varies from 28 to 31 days, so this converter uses the average month of 30.44 days (2,629,800 s) and the Julian year of 365.25 days (31,557,600 s), which accounts for leap years. Use exact calendar dates rather than these averages when the specific month matters.
Worked example. A 90-minute meeting is 90 × 60 = 5,400 seconds, or 1.5 hours. A 30-day billing period is 30 × 86,400 = 2,592,000 seconds, which is about 4.29 weeks. And a one-million-second countdown works out to 1,000,000 ÷ 86,400 ≈ 11.57 days.
Where it's used. Time conversion appears in payroll and timesheets, cooking and fermentation schedules, subscription and warranty periods, and constantly in software — cache lifetimes, session timeouts and API rate limits are typically specified in seconds or milliseconds while humans think in hours and days. For an exact count between two specific calendar dates, including leap years, use the date difference calculator instead.