Time Unit Converter
Convert between ms, seconds, minutes, hours and days
How to use Time Unit Converter
Convert between milliseconds, seconds, minutes, hours, days and weeks. Instant results. Free online time unit converter tool.
When do you need to convert time units?
Time unit conversions appear constantly in programming, project management, physics, and everyday scheduling. The non-decimal nature of time (60 seconds per minute, 24 hours per day) makes mental conversion error-prone.
- Programming and performance: APIs return timestamps in milliseconds (Unix time in ms), while humans think in seconds, minutes, and hours. A response time of 2,847ms is 2.847 seconds — instant conversion helps interpret performance metrics.
- Service Level Agreements (SLAs): "99.9% uptime" means 8.77 hours of allowed downtime per year. Convert to understand what SLA tiers actually mean in practice.
- Caching and TTL: Cache time-to-live values are set in seconds. A 7-day cache = 604,800 seconds. Convert confidently without mental arithmetic.
- Physics problems: Velocity, acceleration, and decay rates often require converting between time units — frequency in Hz (cycles/second) to cycles/minute, or radioactive half-life in seconds to years.
- Project timelines: Convert estimated work hours to days and weeks for scheduling. 240 hours = 30 working days = 6 working weeks.
Useful reference: 1 minute = 60 seconds. 1 hour = 3,600 seconds. 1 day = 86,400 seconds. 1 week = 604,800 seconds. 1 year ≈ 31,536,000 seconds (365 days) or 31,557,600 seconds (365.25 days including leap years).
Frequently Asked Questions
What is Unix time (epoch time)?
Unix time counts seconds since January 1, 1970, 00:00:00 UTC (the Unix epoch). As of 2025, it is approximately 1,746,000,000 seconds. It is used in all programming languages and systems for storing and comparing timestamps — a single integer that is timezone-independent and easily sortable.
What is the Year 2038 problem?
32-bit Unix timestamps overflow on January 19, 2038 at 03:14:07 UTC, when the count exceeds 2^31-1 (2,147,483,647). Systems using 32-bit signed integers to store Unix time will fail. Most modern systems use 64-bit integers, which are safe until the year 292,277,026,596.
How many seconds are in a year?
365 days × 24 hours × 60 minutes × 60 seconds = 31,536,000 seconds. A leap year has 31,622,400 seconds. The Julian year (used in astronomy) is exactly 365.25 days = 31,557,600 seconds. The Gregorian year averages 365.2425 days = 31,556,952 seconds.
What is the difference between milliseconds and microseconds?
1 millisecond (ms) = 1/1,000 of a second (10^-3). 1 microsecond (μs) = 1/1,000,000 of a second (10^-6). 1 nanosecond (ns) = 1/1,000,000,000 of a second (10^-9). CPU operations happen in nanoseconds; network requests in milliseconds; human perception threshold is about 100ms.
What is the difference between duration and interval?
Duration is the length of time something takes — measured in seconds, minutes, hours. Interval is the time between recurring events — the gap between two timestamps. Both are measured in the same units, but the context differs: 'the task took 45 minutes' (duration) vs 'the task runs every 45 minutes' (interval).
Seconds vs milliseconds vs Unix timestamp vs ISO 8601
Seconds are the SI base unit — used for physics, chemistry, and most scientific work. Milliseconds are the standard in computing for response times, timeouts, and timestamps. Unix timestamps (seconds or ms since epoch) are the universal format for storing and transmitting time in systems — timezone-independent and sortable. ISO 8601 (2025-04-10T14:30:00Z) is the human-readable international standard for date-time strings. Use Unix time for computation, ISO 8601 for display and data interchange.