How many seconds in a year, how many hours in a month?
Time unit converter for milliseconds, seconds, minutes, hours, days, weeks, months, years. Type a value in one unit, see it instantly in all the others.
This is NOT a date converter. If you want "what date was 3 years ago?", use our date difference calculator. This converts amounts of time, like "how many seconds fit in an hour".
How to use it
- Type a value and pick a unit (e.g. hour, day, year).
- The other time units show the conversion automatically.
- Click any tile to copy the result.
When this is useful
Six typical situations where the converter saves you mental math:
- Programming, application timeout: "5000 ms is how many seconds?" (5). "60-minute pause, how many ms?" (3,600,000).
- Project planning: "how many hours in 3 months of full-time work?" (520 working hours).
- Hourly rate scaling: "10 hours per week × 52 weeks, how many hours per year?" (520).
- Education, fun facts: "how many seconds in a year?" (~31.5 million). "How many minutes does a person live in 80 years?" (42 million).
- Sleep tracking: "8 hours of sleep × 365 days, how many days of sleep per year?" (122 days).
- Apps: timeout, interval, scheduling parameters, all in different units.
Questions and answers
1 year = 31,556,952 seconds (about 31.5 million). Exactly 365.2425 days × 24 × 60 × 60. Easy mnemonic: about π × 10⁷ seconds (3.14 × 10 million ≈ 31.4 million).