Second to Calendar Year
s
yr
Conversion History
| Conversion | Reuse | Delete |
|---|---|---|
1 s (Second) → 3.170979198376e-8 yr (Calendar Year) Just now |
Quick Reference Table (Second to Calendar Year)
| Second (s) | Calendar Year (yr) |
|---|---|
| 1 | 0.00000003170979198376 |
| 10 | 0.00000031709791983765 |
| 60 | 0.00000190258751902588 |
| 100 | 0.00000317097919837646 |
| 3,600 | 0.00011415525114155251 |
| 86,400 | 0.00273972602739726027 |
| 31,536,000 | 1 |
About Second (s)
The second (s) is the SI base unit of time, defined as exactly 9,192,631,770 periods of the radiation of the caesium-133 atom in its ground state hyperfine transition. Before 1967 it was defined as 1/86,400 of a mean solar day, but atomic clocks now provide a definition independent of Earth's rotation. The second is the foundation of all time measurement — minutes, hours, and days are multiples of seconds. In physics and engineering, time is always converted to seconds for calculations. The second is also the unit in which speed of light and gravitational constants are expressed.
A human heartbeat at rest is about 1 second. Light travels 299,792 km in 1 second. The 100 m sprint world record is under 10 seconds.
Etymology: From Latin 'secunda minuta' (second small part), contrasted with 'prima minuta' (first small part, i.e. the minute). The hour was divided into 60 minutes and the minute into 60 seconds — both steps inheriting the sexagesimal (base-60) system of ancient Babylonian astronomy.
About Calendar Year (yr)
A calendar year is the time Earth takes to complete one orbit of the Sun — approximately 365.2422 days. The Gregorian calendar approximates this with 365-day common years and 366-day leap years, adding a leap day every 4 years with century-year exceptions. The converter uses exactly 365 days (31,536,000 seconds), the common year. A year is the primary unit for financial reporting, age, historical dating, and long-term planning. The tropical year (used in astronomy) is slightly different from the calendar year. ISO 8601 defines the year as starting on 1 January in the proleptic Gregorian calendar.
A mortgage runs 15 or 30 years. A US presidential term is 4 years. The average lifespan in high-income countries is about 80 years.
Second – Frequently Asked Questions
Why is there a leap second and who decides when to add one?
Earth's rotation is gradually slowing due to tidal friction from the Moon, running slightly slower than the atomic clock definition of the second. To keep UTC (atomic time) within 0.9 seconds of UT1 (astronomical time), leap seconds are periodically inserted — 27 have been added since 1972. The International Earth Rotation and Reference Systems Service (IERS) announces each leap second about 6 months in advance. In 2022, the ITU voted to eliminate leap seconds by 2035, allowing UTC to drift freely.
How many seconds are in a year?
A common year (365 days) contains exactly 31,536,000 seconds. A leap year has 31,622,400 seconds. The mean Gregorian year (365.2425 days) contains 31,556,952 seconds. The tropical year (365.24219 days) — the actual solar cycle — is 31,556,926 seconds. The difference between common year and tropical year (about 926 seconds ≈ 15 minutes) is why a simple 365-day calendar drifts against the seasons without leap year corrections.
Why did the second replace the solar day as the base time unit?
The solar day varies slightly (up to 30 seconds) due to Earth's elliptical orbit and axial tilt — making it unsuitable for precision timekeeping. Atomic clocks, defined by caesium-133 oscillations, are stable to 1 part in 10¹⁶ — drifting less than 1 second in 300 million years. GPS, financial transactions, mobile networks, and the internet all require sub-microsecond synchronisation that only atomic-clock-based seconds can provide.
What is the fastest human 100 m sprint time and why does tenths of a second matter?
Usain Bolt's 9.58 s world record from 2009 is 0.12 s faster than the previous record. At that speed (10.44 m/s average), 0.12 s corresponds to 1.25 m — nearly the length of a stride. Athletics timing uses 0.001 s (1 ms) precision; photo finish cameras operate at 1,000+ frames/second. Olympic medals have been separated by 0.001 s. The reaction time rule (any start under 0.1 s is a false start) is based on the minimum human neural response time.
What did Babylonians have to do with the 60-second minute?
Babylonian astronomers used a sexagesimal (base-60) number system because 60 is divisible by 2, 3, 4, 5, 6, 10, 12, 15, 20, and 30 — making fractions exceptionally convenient without remainders. They divided the sky into 360 degrees (6 × 60) and the day into 24 hours. Greek astronomers adopted and transmitted this system; medieval Islamic scholars refined it; and Europe inherited the 60-minute hour and 60-second minute through Latin translation of Arabic astronomical texts.
Calendar Year – Frequently Asked Questions
Why is a leap year every 4 years — with exceptions?
The tropical year is 365.24219 days. Adding a leap day every 4 years gives 365.25 — close but 0.00781 days too long. Over 400 years that accumulates to 3.1 extra days. The Gregorian rule fixes this: century years (1700, 1800, 1900) skip the leap day, but years divisible by 400 (1600, 2000, 2400) keep it. Result: 365.2425 days/year — accurate to 26 seconds per year, drifting one day in about 3,300 years.
What happened in 1582 when the Gregorian calendar was introduced?
Pope Gregory XIII corrected the Julian calendar, which had drifted 10 days from the astronomical equinox since 325 CE. Catholic countries deleted 10 days: Thursday 4 October 1582 was followed by Friday 15 October. Protestant countries delayed adoption — Britain switched in 1752, deleting 11 days (2 September → 14 September). Russia switched in 1918, deleting 13 days. This is why the "October Revolution" occurred in November under the new calendar.
What is a fiscal year and why does it not always start in January?
A fiscal year (FY) is a 12-month accounting period that may start on any date. The US federal government uses 1 October – 30 September. The UK tax year runs 6 April – 5 April (a date inherited from the Julian-to-Gregorian calendar switch: the old new year was 25 March, which shifted to 5 April after the 11-day deletion). Australia's FY is 1 July – 30 June. Companies choose fiscal years to align with seasonal revenue patterns.
How old is the universe in years?
The universe is approximately 13.787 billion years old, determined from measurements of the cosmic microwave background (Planck satellite data, 2018). The oldest known star (HD 140283, 'Methuselah star') is about 14.46 ± 0.80 billion years — uncertainties in stellar age models make this compatible with the universe's age. Earth is 4.54 billion years old. Modern humans (Homo sapiens sapiens) have existed for about 300,000 years — 0.0022% of Earth's age.
What calendar does Ethiopia use and why is it different?
Ethiopia uses the Ethiopian calendar, which has 13 months (12 of 30 days + a 13th month of 5 or 6 days). It is currently about 7–8 years behind the Gregorian calendar because Ethiopian Christianity followed a different calculation for the year of Jesus's birth. Ethiopia celebrated its millennium (year 2000) in September 2007. This is why Ethiopian Airlines advertises '13 months of sunshine' — their calendar has a literal 13th month.