[SOLVED] Is there a better way in C# to round a DateTime to the nearest 5 seconds?

Issue

I want to round a DateTime to the nearest 5 seconds. This is the way I’m currently doing it but I was wondering if there was a better or more concise way?

DateTime now = DateTime.Now;
int second = 0;

// round to nearest 5 second mark
if (now.Second % 5 > 2.5)
{
    // round up
    second = now.Second + (5 - (now.Second % 5));
}
else
{
    // round down
    second = now.Second - (now.Second % 5);
}

DateTime rounded = new DateTime(now.Year, now.Month, now.Day, now.Hour, now.Minute, second);

Please note that I’ve found these two previous questions, however they truncate rather than round the time.

Solution

The Ticks count of a DateTime represents 100-nanosecond intervals, so you can round to the nearest 5 seconds by rounding to the nearest 50000000-tick interval like this:

  DateTime now = DateTime.Now;
  DateTime rounded = new DateTime(((now.Ticks + 25000000) / 50000000) * 50000000);

That’s more concise, but not necessarily better. It depends on whether you prefer brevity and speed over code clarity. Yours is arguably easier to understand.

Answered By – JayMcClellan

Answer Checked By – Dawn Plyler (BugsFixing Volunteer)