## DEV Community

Ricardo

Posted on • Originally published at rmauro.dev on

# Calculate Time Ago with C#

Here is a small extension method over System.DateTime that gives its relative time readable for humans, such as:

• one minute ago
• 2 minutes ago
• one hour ago
• 3 hours ago
• 3 days ago

Check out this extension method over the DateTime structure using switch patterns.

``````public static string AsTimeAgo(this DateTime dateTime)
{
TimeSpan timeSpan = DateTime.Now.Subtract(dateTime);

return timeSpan.TotalSeconds switch
{
<= 60 => \$"{timeSpan.Seconds} seconds ago",

_ => timeSpan.TotalMinutes switch
{
<= 1 => "about a minute ago",
< 60 => \$"about {timeSpan.Minutes} minutes ago",
_ => timeSpan.TotalHours switch
{
<= 1 => "about an hour ago",
< 24 => \$"about {timeSpan.Hours} hours ago",
_ => timeSpan.TotalDays switch
{
<= 1 => "yesterday",
<= 30 => \$"about {timeSpan.Days} days ago",

<= 60 => "about a month ago",
< 365 => \$"about {timeSpan.Days / 30} months ago",

<= 365 * 2 => "about a year ago",
_ => \$"about {timeSpan.Days / 365} years ago"
}
}
}
};
}
``````

Extension method AsTimeAgo

## Bonus! Different solutions for the same problem

Surfing the web - I'm so old - I found two more solutions for the same problem.

Tell me in the comments section which one you like the best.

### First Solution

``````const int SECOND = 1;
const int MINUTE = 60 * SECOND;
const int HOUR = 60 * MINUTE;
const int DAY = 24 * HOUR;
const int MONTH = 30 * DAY;

var ts = new TimeSpan(DateTime.UtcNow.Ticks - yourDate.Ticks);
double delta = Math.Abs(ts.TotalSeconds);

if (delta < 1 * MINUTE)
return ts.Seconds == 1 ? "one second ago" : ts.Seconds + " seconds ago";

if (delta < 2 * MINUTE)
return "a minute ago";

if (delta < 45 * MINUTE)
return ts.Minutes + " minutes ago";

if (delta < 90 * MINUTE)
return "an hour ago";

if (delta < 24 * HOUR)
return ts.Hours + " hours ago";

if (delta < 48 * HOUR)
return "yesterday";

if (delta < 30 * DAY)
return ts.Days + " days ago";

if (delta < 12 * MONTH)
{
int months = Convert.ToInt32(Math.Floor((double)ts.Days / 30));
return months <= 1 ? "one month ago" : months + " months ago";
}
else
{
int years = Convert.ToInt32(Math.Floor((double)ts.Days / 365));
return years <= 1 ? "one year ago" : years + " years ago";
}

``````

Found on https://stackoverflow.com/questions/11/calculate-relative-time-in-c-sharp

### Second Solution

``````public static string TimeAgo(this DateTime dateTime)
{
string result = string.Empty;
var timeSpan = DateTime.Now.Subtract(dateTime);

if (timeSpan <= TimeSpan.FromSeconds(60))
{
result = string.Format("{0} seconds ago", timeSpan.Seconds);
}
else if (timeSpan <= TimeSpan.FromMinutes(60))
{
result = timeSpan.Minutes > 1 ?
String.Format("about {0} minutes ago", timeSpan.Minutes) :
"about a minute ago";
}
else if (timeSpan <= TimeSpan.FromHours(24))
{
result = timeSpan.Hours > 1 ?
String.Format("about {0} hours ago", timeSpan.Hours) :
"about an hour ago";
}
else if (timeSpan <= TimeSpan.FromDays(30))
{
result = timeSpan.Days > 1 ?
String.Format("about {0} days ago", timeSpan.Days) :
"yesterday";
}
else if (timeSpan <= TimeSpan.FromDays(365))
{
result = timeSpan.Days > 30 ?
String.Format("about {0} months ago", timeSpan.Days / 30) :
"about a month ago";
}
else
{
result = timeSpan.Days > 365 ?
String.Format("about {0} years ago", timeSpan.Days / 365) :
"about a year ago";
}

return result;
}

``````

Found on https://dotnetthoughts.net/time-ago-function-for-c/

Forward to a friend and let them know.

## Top comments (3)

Galdin Raphael

If you've not seen this already, there's also github.com/Humanizr/Humanizer :)

Ricardo

I haven’t seen it before. I love it.
Thanks for sharing

CodeFilez

Pretty cool :)