Seconds to Years Converter
Convert seconds to years — one year is 31,556,952 seconds on the Gregorian average. Results update as you type; exact factors shown.
One second is 3.1689e-8 year (365.2425 days) — see the exact factor, not a rounded rule of thumb.
How the seconds to years converter works
Time converts through the second. Minutes, hours, days and weeks are exact multiples. A month is taken as the Gregorian average (30.436875 days) and a year as the Gregorian average (365.2425 days = 31,556,952 s); calendar months and leap years vary from these averages.
The UK is metric for most trade and science but keeps miles, pints, stone and mpg (with the imperial gallon) in daily life.
Common time conversions
| From | To | Units |
|---|---|---|
| 86,400 s | 0.0027 yr | seconds to year (365.2425 days) |
| 604,800 s | 0.0192 yr | seconds to year (365.2425 days) |
| 1,000,000 s | 0.0317 yr | seconds to year (365.2425 days) |
| 2,629,746 s | 0.0833 yr | seconds to year (365.2425 days) |
| 10,000,000 s | 0.3169 yr | seconds to year (365.2425 days) |
| 31,536,000 s | 0.9993 yr | seconds to year (365.2425 days) |
| 31,556,952 s | 1 yr | seconds to year (365.2425 days) |
| 100,000,000 s | 3.1689 yr | seconds to year (365.2425 days) |
| 315,569,520 s | 10 yr | seconds to year (365.2425 days) |
| 1,000,000,000 s | 31.6887 yr | seconds to year (365.2425 days) |
| 3,155,695,200 s | 100 yr | seconds to year (365.2425 days) |
| 10,000,000,000 s | 316.8874 yr | seconds to year (365.2425 days) |
Units in this converter and their exact factors
| Unit | Symbol | One unit in seconds |
|---|---|---|
| millisecond | ms | 0.001 second |
| second | s | 1 second |
| minute | min | 60 second |
| hour | h | 3,600 second |
| day | d | 86,400 second |
| week | wk | 604,800 second |
| month (average, 30.4369 days) | mo | 2,629,746 second |
| year (365.2425 days) | yr | 31,556,952 second |
FAQFrequently asked questions about time conversion
How many seconds in a year?
31,556,952 on the Gregorian average; a common year of 365 days has 31,536,000.
What is a billion seconds in years?
31.69 years.
What is a million seconds?
About 11.6 days — far shorter than most people guess.
Why is a billion seconds so much longer than a million?
Because a billion is a thousand millions: 11.6 days becomes 31.7 years.
Is a year exactly 31.5 million seconds?
Close — 31,556,952, which is often approximated as pi times ten million (31,415,927), accurate to half a percent.
Where these figures come from
- BIPM — The International System of Units (SI Brochure, 9th edition) — definitions of the base and derived units.
- NIST Special Publication 811 — Guide for the Use of the International System of Units — the exact conversion factors used here.
- National Physical Laboratory (NPL) — United Kingdom's national measurement authority.
Last checked: September 2026. Conversion factors are fixed by definition and do not change with tax years or regulations.