Time & Dates
Days between two dates
The difference between two day numbers is the exact number of days between the dates.
The Formula
Days = JDN(to) - JDN(from)
The difference between two day numbers is the exact number of days between the dates.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| JDN from | From day number | day | The Julian day number of the starting date. |
| JDN to | To day number | day | The Julian day number of the ending date. |
What Each Symbol Means
JDN fromday
From day number
The Julian day number of the starting date.
JDN today
To day number
The Julian day number of the ending date.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate days between dates page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate Days Between Dates, filed under Everyday Life. Every number the guide produces comes from substituting into this one line.