# Seconds to Years Converter URL: https://speedycalculator.com/calculators/conversion/seconds-to-years-conversion/ Last updated: 2026-10-25 > Convert seconds (s) to years (year): 1 second = 3.168874 × 10^-8 year, so multiply by 3.168874 × 10^-8 or divide by 31,556,952. Both fields are editable, so you can also type in years and get seconds back. ## Inputs - Seconds (s) ## Results - Years ## Formula ``` 1 s = 3.168874 × 10^-8 year 1 year = 31,556,952 s year = s × 3.168874 × 10^-8 ``` ## Explanation An average Gregorian year has 31,556,952 seconds. One billion seconds is about 31.7 years. ### How to use the Seconds to Years Converter - Type the number of seconds into the **Seconds** field. Decimals such as 500,000,000 are fine. - Read the answer in **Years** – it updates as you type, with no button to press. - To convert the other way, type into **Years** and the seconds are recalculated. - Press **Copy results** to copy both values with the page title, or **Copy link** to share this exact conversion. This page converts only s ⇄ year. Need a different unit? Use the general time converter, where you can choose any “from” and “to” unit. ### How it works Both units measure time, so they are always in the same ratio: one second equals 3.168874 × 10^-8 years. The calculator multiplies the number of seconds you type by 3.168874 × 10^-8 to give years, and when you type into the years field it divides by the same factor to give seconds. Because the ratio never changes, doubling the seconds always doubles the years. Results are calculated at full precision and rounded only for display (up to eight decimal places, with very large or small values shown in scientific notation). ### How to convert seconds to years - Write down the value in seconds, for example **1 × 109 s**. - Multiply by the conversion factor 3.168874 × 10-8 (because 1 second = 3.168874 × 10-8 year). - 1 × 109 × 3.168874 × 10-8 = **31.688739 year**. - To go back from years to seconds, divide by 3.168874 × 10-8 – or multiply by 31,556,952. ### s to year conversion table SecondsYearsYearsSeconds1,000,000 s0.031688739 year1 year31,556,952 s10,000,000 s0.31688739 year2 year63,113,904 s31,556,952 s1 year5 year157,784,760 s100,000,000 s3.1688739 year10 year315,569,520 s1 × 109 s31.688739 year20 year631,139,040 s1 × 1010 s316.88739 year50 year1.577848 × 109 s100 year3.155695 × 109 s1,000 year3.155695 × 1010 s ### What is a second? The second is the SI base unit of time, defined by 9,192,631,770 cycles of radiation from a caesium-133 atom. ### What is a year? A calendar year has 365 or 366 days. The average Gregorian year, 365.2425 days, accounts for the leap-year rules. ### Quick mental conversion For a fast estimate, multiply seconds by about **3.2 × 10-8** to get years; the error is about 1.0%. Use the calculator above when you need the exact figure. ### Common mistakes to avoid Treating every month as 30 days or every year as 365 days in long calculations, and writing decimal hours such as 1.5 h as 1 h 50 min (it is 1 h 30 min). ## Worked example Inputs — Seconds: 1,000,000,000 s. Results — **Years = 31.68873851 year**. ## FAQ **How many years is a billion seconds?** About 31.7 years. **How many seconds in a year?** 31,536,000 (365 days) or 31,556,952 on average. **How do I convert seconds to years?** Multiply the number of seconds by 3.168874 × 10^-8. For example, 1 × 10^9 s × 3.168874 × 10^-8 = 31.688739 year. **How do I convert years back to seconds?** Divide by 3.168874 × 10^-8 (or multiply by 31,556,952), or simply type the value into the years field above. **What is 1,000,000 s in years?** 1,000,000 s = 0.031688739 year. **What is 10,000,000 s in years?** 10,000,000 s = 0.31688739 year. **Is this conversion exact?** Yes. The factor comes from the official definitions of both units (NIST and the SI), so the only difference you may see is rounding in the last displayed digit. **Can I convert to other units on this page?** This page converts only between seconds and years. To pick any time unit, use the general time converter linked under Related calculators. **What formula does the Seconds to Years Converter use?** 1 s = 3.168874 × 10^-8 year. ## Sources - [NIST Special Publication 811 – Guide for the Use of the International System of Units](https://www.nist.gov/pml/special-publication-811) - [NIST Handbook 44 Appendix C – General tables of units of measurement](https://www.nist.gov/pml/owm/nist-handbook-44-current-edition)