Ticks 640000000000000000

For more than 20 years I've been looking at DateTime.Ticks Int64 values and they always look like 63nnnnnnnnnnnnnnnn, and I was wondering how long we must wait until the leading digits become 64. A little bit of C# script using the DateTimeOffset struct created the following table of waypoint tick values along the way to January 2029.

If you want to wait until the leading digit changes from 6 to 7 then we have to wait until Saturday, 20 March 2219 04:26:40.

If you're wondering when the 64‑bit signed Ticks value will overflow and cause a new epochal form of millenium bug, then we have to wait about 29.2 million years.

Ticks Breakdown

Here is a nice breakdown of the digits in a Ticks value. Remember that the least significant digit (rightmost) is 100 nanoseconds (10^-7 seconds).

Doodling

The Ticks property documentation says:

The value of this property represents the number of 100-nanosecond intervals that have elapsed since 12:00:00 midnight, January 1, 0001 in the Gregorian calendar, which represents MinValue.

Taking the popular approximation for the average length of a year being 365.25 days, we can divide the Ticks value by the number of 100 nanoseconds in an average year and add one (there was no year zero!) to get the approximate current year.

$$\frac{\mathrm{638893213025970129}}{60\times 60\times 24\times 365.35\times {10}^7}+1=2025.530424$$

The actual value is 2025.571883 years, so it's close enough for jazz, ignoring some as yet unidentified rounding issues.