Time Converter
Convert between seconds, minutes, hours, days, weeks, months, and years.
Time conversions span from the microscopic (nanoseconds in computing) to the cosmic (light-years as a time-distance hybrid). In everyday life, the most common conversions involve hours, minutes, seconds, and the sometimes confusing relationship between days, weeks, months, and years. Understanding how time units relate to each other is essential for project planning, scientific measurement, and converting durations across different formats.
Popular Time Conversions
Standards Note: The Second Is Atomic
NIST explains that the SI second is defined by exactly 9,192,631,770 cycles of the cesium-133 resonance frequency, not by the Earth’s rotation.
Source: A Walk Through Time - The "Atomic Age" of Time Standards | NIST
The SI System and the Second
The second is the SI base unit of time, defined since 1967 as exactly 9,192,631,770 oscillations of the cesium-133 atom — a definition accurate to within 1 second over 300 million years. From seconds, all other metric time units are derived: milliseconds (10⁻³ s), microseconds (10⁻⁶ s), nanoseconds (10⁻⁹ s), and picoseconds (10⁻¹² s) are used in electronics, computing, and physics. Minutes, hours, and days are not SI units — they're historical conventions that exist alongside the metric system.
Days, Weeks, Months, and Years
A calendar year averages 365.2422 days, which is why we add a leap day every 4 years (with century exceptions). A month ranges from 28 to 31 days, making exact month-to-day conversions impossible without knowing which months are involved. For rough calculations, use 30.44 days per month or 365.25 days per year. One week is always exactly 7 days, making it the most reliable non-SI time unit for scheduling. A decade is 10 years; a century is 100 years.
| Unit | Value |
|---|---|
| 1 minute | 60 seconds |
| 1 hour | 3,600 seconds |
| 1 day | 86,400 seconds |
| 1 week | 604,800 seconds / 7 days |
| 1 month (avg) | ~30.44 days |
| 1 year | 365.25 days (average) |
| 1 decade | 10 years / 3,652–3,653 days |
Time in Computing
Computers work in nanoseconds and microseconds. A modern 3 GHz processor executes roughly 3 billion cycles per second — each cycle takes about 0.33 nanoseconds. Network round-trip times (latency) are measured in milliseconds: a ping of 20 ms to a game server is imperceptible, while 200 ms is noticeable. Hard drives and SSDs are rated in IOPS (I/O operations per second); an NVMe SSD might deliver 500,000 IOPS with microsecond latency. UNIX timestamps count the number of seconds since January 1, 1970 (UTC) — the foundation of time representation in most programming languages.
How to convert hours to minutes and minutes to seconds | Khan Academy
Khan Academy gives a short, concrete refresher on the two time conversions people use most often when moving between clock time and total duration.
Video source: Khan Academy
Further Reading
Sources & References
- NIST — Units and Conversion Factors — Official unit conversion factors from the National Institute of Standards and Technology.
- BIPM — The International System of Units (SI) — International SI unit definitions from the International Bureau of Weights and Measures.