Years to Days Converter
Enter the time in years below to convert it to days.
Convert Years to Days
Enter a value in years (yr) to convert to days (d).
Year to Day Conversion Table
Table showing various year measurements converted to days. Click any preset value or arrow to load it into the converter.
| Years (yr) | Days (d) |
|---|---|
| 1 yr | 365.2425 d |
| 2 yr | 730.485 d |
| 2.5 yr | 913.10625 d |
| 5 yr | 1,826.2125 d |
| 10 yr | 3,652.425 d |
| 15 yr | 5,478.6375 d |
| 20 yr | 7,304.85 d |
| 25 yr | 9,131.0625 d |
| 30 yr | 10,957.275 d |
| 50 yr | 18,262.125 d |
How to Convert Years to Days
To convert years to days, multiply the time by the following conversion ratio: 365.2425 days/year.
Since one year is equal to 365.2425 days, you can use this simple formula to convert:
The time in days is equal to the time in years multiplied by 365.2425.
For example, here's how to convert 5 years to days using the formula above.
How Many Days Are in a Year?
There are 365.2425 days in a year, which is why we use this value in the formula above.
Our year to day calculator automatically converts your time measurements with full decimal and scientific precision across US customary, imperial, and SI metric standards.
Years and days are both units used to measure time. Keep reading to learn more about each unit.
What Is a Year?
A year is a unit of time equal to 31,556,952 seconds (s), the base unit for time. Average Gregorian calendar year (31,556,952 seconds). [1]
The year is classified as a standard unit of time. Years can be abbreviated as yr; for example, 1 year can be written as 1 yr.
When working with years (yr) in formulas or technical specifications, always verify whether your target system uses SI metric, US customary, or British imperial standards.
In practice, years (yr) are widely used across large-scale industrial, bulk, and macro-level time specifications within international standard workflows, engineering documentation, and technical data sheets.
What Is a Day?
A day is a unit of time equal to 86,400 seconds (s), the base unit for time. Civil day equal to 24 hours or 86,400 seconds. [2]
The day is classified as a standard unit of time. Days can be abbreviated as d; for example, 1 day can be written as 1 d.
When working with days (d) in formulas or technical specifications, always verify whether your target system uses SI metric, US customary, or British imperial standards.
In practice, days (d) are widely used across large-scale industrial, bulk, and macro-level time specifications within international standard workflows, engineering documentation, and technical data sheets.
When converting time between years (yr) and days (d), keep full floating-point precision (1 yr = 365.2425 d; 1 d = 0.0027379 yr) during intermediate calculations and round only the final day figure to match your instrument tolerance.
More Year & Day Conversions
Need to calculate in the opposite direction? Use our days to years converter (d to yr) to switch your starting unit immediately. You can also explore related tools such as converting hours to days, converting weeks to days, or converting years to months.
Frequently Asked Questions
References
- [1]NIST OWM StandardNIST OWM (SI Units — Time)·Time Metrology Standard — Years (yr) to Days (d)
- [2]BIPM SpecificationBIPM (SI Base Unit: Second (s))·Unit Specifications: Year (Gregorian 365.2425 d) (yr) & Day (d)
- [3]NIST CUU ReferenceNIST CUU (Non-SI Units Accepted for Use (min, h, d))·Conversion Factors & Mathematical Basis (yr to d)