Console.WriteLine(Convert.ToDouble(DateTime.UtcNow.Ticks - 621355968000000000) / (10 * 1000 * 1000)); TimeSpan ts1 = DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, 0); TimeSpan ts2 = new TimeSpan(DateTime.Now.ToUniversalTime().Ticks - 621355968000000000); TimeSpan ts3 = new TimeSpan(DateTime.UtcNow.Ticks - 621355968000000000); Console.WriteLine(ts1.TotalSeconds); Console.WriteLine(ts2.TotalSeconds); Console.WriteLine(ts3.TotalSeconds); Console.ReadLine();