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To convert leap years to days: multiply by 366. To seconds: multiply by 31,622,400.
1 leap year = 366 d = 8,784 h = 527,040 min = 31,622,400 s. That's 86,400 s more than a common year.
For example, 1 Year (Leap) (yr (Leap)) = 0.01002739726 Century (cen).
| Year (Leap) (yr (Leap)) | Century (cen) |
|---|---|
| 0.1 | 0.001002739726 |
| 0.5 | 0.00501369863 |
| 1 | 0.01002739726 |
| 2 | 0.02005479452 |
| 5 | 0.0501369863 |
| 10 | 0.1002739726 |
| 25 | 0.2506849315 |
| 50 | 0.501369863 |
| 100 | 1.002739726 |
| 500 | 5.01369863 |
| 1000 | 10.02739726 |
A leap year is a calendar year containing 366 days (31,622,400 seconds), with an extra day added as February 29th to correct calendar drift.
1 leap year = 366 d = 8,784 h = 527,040 min = 31,622,400 s. That's 86,400 s more than a common year.
To convert leap years to days: multiply by 366. To seconds: multiply by 31,622,400.
Calendar systems, date arithmetic in software (handling Feb 29), birthday celebrations for 'leaplings,' and financial calculations.
People born on February 29 are called 'leaplings' — they technically have a birthday only once every 4 years. The odds of being born on Feb 29 are about 1 in 1,461.
The most common bug: not handling Feb 29. Many software failures have occurred on leap day. Also, the 100/400 rule is often forgotten.
Leap year test: divisible by 4? Yes → leap year, UNLESS divisible by 100, UNLESS also divisible by 400. Code it: (y%4==0 && y%100!=0) || y%400==0.
A century is a unit of time equal to 100 years, or approximately 36,525 days (3,153,600,000 seconds based on 365-day years).
1 century = 100 years = 10 decades = 1,200 months ≈ 36,525 average days.
To convert centuries to years: multiply by 100. To decades: multiply by 10.
Historical periodization, infrastructure planning (century-old bridges), and long-term climate projections.
The Gregorian calendar gained only about 1 day of error per 3,236 years — meaning it stays accurate for centuries without adjustment.
The 21st century began on January 1, 2001 — not 2000. There was no year 0, so the first century was years 1–100.
Century numbering: the 1900s = 20th century. Add 1 to the hundreds: 1800s = 19th century, 2000s = 21st century.



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