How can I round up the time to the nearest X minutes?

C#DatetimeRounding

C# Problem Overview

Is there a simple function for rounding UP a DateTime to the nearest 15 minutes?

E.g.

2011-08-11 16:59 becomes 2011-08-11 17:00

2011-08-11 17:00 stays as 2011-08-11 17:00

2011-08-11 17:01 becomes 2011-08-11 17:15

C# Solutions

Solution 1 - C#

DateTime RoundUp(DateTime dt, TimeSpan d)
{
    return new DateTime((dt.Ticks + d.Ticks - 1) / d.Ticks * d.Ticks, dt.Kind);
}

Example:

var dt1 = RoundUp(DateTime.Parse("2011-08-11 16:59"), TimeSpan.FromMinutes(15));
// dt1 == {11/08/2011 17:00:00}

var dt2 = RoundUp(DateTime.Parse("2011-08-11 17:00"), TimeSpan.FromMinutes(15));
// dt2 == {11/08/2011 17:00:00}

var dt3 = RoundUp(DateTime.Parse("2011-08-11 17:01"), TimeSpan.FromMinutes(15));
// dt3 == {11/08/2011 17:15:00}

Solution 2 - C#

Came up with a solution that doesn't involve multiplying and dividing long numbers.

public static DateTime RoundUp(this DateTime dt, TimeSpan d)
{
var modTicks = dt.Ticks % d.Ticks;
var delta = modTicks != 0 ? d.Ticks - modTicks : 0;
return new DateTime(dt.Ticks + delta, dt.Kind);
}




public static DateTime RoundDown(this DateTime dt, TimeSpan d)
{
var delta = dt.Ticks % d.Ticks;
return new DateTime(dt.Ticks - delta, dt.Kind);
}




public static DateTime RoundToNearest(this DateTime dt, TimeSpan d)
{
var delta = dt.Ticks % d.Ticks;
bool roundUp = delta > d.Ticks / 2;
var offset = roundUp ? d.Ticks : 0;



return new DateTime(dt.Ticks + offset - delta, dt.Kind);




}
}

Usage:

var date = new DateTime(2010, 02, 05, 10, 35, 25, 450); // 2010/02/05 10:35:25
var roundedUp = date.RoundUp(TimeSpan.FromMinutes(15)); // 2010/02/05 10:45:00
var roundedDown = date.RoundDown(TimeSpan.FromMinutes(15)); // 2010/02/05 10:30:00
var roundedToNearest = date.RoundToNearest(TimeSpan.FromMinutes(15)); // 2010/02/05 10:30:00

Solution 3 - C#

if you need to round to a nearest time interval (not up) then i suggest to use the following

    static DateTime RoundToNearestInterval(DateTime dt, TimeSpan d)
    {
        int f=0;
        double m = (double)(dt.Ticks % d.Ticks) / d.Ticks;
        if (m >= 0.5)
            f=1;            
        return new DateTime(((dt.Ticks/ d.Ticks)+f) * d.Ticks);
    }

Solution 4 - C#

void Main()
{
	var date1 = new DateTime(2011, 8, 11, 16, 59, 00);
    date1.Round15().Dump();
    
    var date2 = new DateTime(2011, 8, 11, 17, 00, 02);
    date2.Round15().Dump();
    
    var date3 = new DateTime(2011, 8, 11, 17, 01, 23);
    date3.Round15().Dump();
    
    var date4 = new DateTime(2011, 8, 11, 17, 00, 00);
    date4.Round15().Dump();
}

public static class Extentions
{
    public static DateTime Round15(this DateTime value)
    {   
        var ticksIn15Mins = TimeSpan.FromMinutes(15).Ticks;
        
        return (value.Ticks % ticksIn15Mins == 0) ? value : new DateTime((value.Ticks / ticksIn15Mins + 1) * ticksIn15Mins);
    }
}

Results:

8/11/2011 5:00:00 PM
8/11/2011 5:15:00 PM
8/11/2011 5:15:00 PM
8/11/2011 5:00:00 PM

Solution 5 - C#

I've seen a nuber of useful implementations, like the one from @dtb or @redent84. Since the performance difference is negligible, I stayed away from bit shifts and simply created readable code. I often use these extensions in my utility libraries.

public static class DateTimeExtensions
{
    public static DateTime RoundToTicks(this DateTime target, long ticks) => new DateTime((target.Ticks + ticks / 2) / ticks * ticks, target.Kind);
    public static DateTime RoundUpToTicks(this DateTime target, long ticks) => new DateTime((target.Ticks + ticks - 1) / ticks * ticks, target.Kind);
    public static DateTime RoundDownToTicks(this DateTime target, long ticks) => new DateTime(target.Ticks / ticks * ticks, target.Kind);

    public static DateTime Round(this DateTime target, TimeSpan round) => RoundToTicks(target, round.Ticks);
    public static DateTime RoundUp(this DateTime target, TimeSpan round) => RoundUpToTicks(target, round.Ticks);
    public static DateTime RoundDown(this DateTime target, TimeSpan round) => RoundDownToTicks(target, round.Ticks);

    public static DateTime RoundToMinutes(this DateTime target, int minutes = 1) => RoundToTicks(target, minutes * TimeSpan.TicksPerMinute);
    public static DateTime RoundUpToMinutes(this DateTime target, int minutes = 1) => RoundUpToTicks(target, minutes * TimeSpan.TicksPerMinute);
    public static DateTime RoundDownToMinutes(this DateTime target, int minutes = 1) => RoundDownToTicks(target, minutes * TimeSpan.TicksPerMinute);

    public static DateTime RoundToHours(this DateTime target, int hours = 1) => RoundToTicks(target, hours * TimeSpan.TicksPerHour);
    public static DateTime RoundUpToHours(this DateTime target, int hours = 1) => RoundUpToTicks(target, hours * TimeSpan.TicksPerHour);
    public static DateTime RoundDownToHours(this DateTime target, int hours = 1) => RoundDownToTicks(target, hours * TimeSpan.TicksPerHour);


    public static DateTime RoundToDays(this DateTime target, int days = 1) => RoundToTicks(target, days * TimeSpan.TicksPerDay);
    public static DateTime RoundUpToDays(this DateTime target, int days = 1) => RoundUpToTicks(target, days * TimeSpan.TicksPerDay);
    public static DateTime RoundDownToDays(this DateTime target, int days = 1) => RoundDownToTicks(target, days * TimeSpan.TicksPerDay);
}

Solution 6 - C#

Since I hate reinventing the wheel, I'd probably follow this algorithm to round a DateTime value to a specified increment of time (Timespan):

  • Convert the DateTime value to be rounded to a decimal floating-point value representing the whole and fractional number of TimeSpan units.
  • Round that to an integer, using Math.Round().
  • Scale back to ticks by multiplying the rounded integer by the number of ticks in the TimeSpan unit.
  • Instantiate a new DateTime value from the rounded number of ticks and return it to the caller.

Here's the code:

public static class DateTimeExtensions
{
    
    public static DateTime Round( this DateTime value , TimeSpan unit )
    {
        return Round( value , unit , default(MidpointRounding) ) ;
    }
    
    public static DateTime Round( this DateTime value , TimeSpan unit , MidpointRounding style )
    {
        if ( unit <= TimeSpan.Zero ) throw new ArgumentOutOfRangeException("unit" , "value must be positive") ;
        
        Decimal  units        = (decimal) value.Ticks / (decimal) unit.Ticks ;
        Decimal  roundedUnits = Math.Round( units , style ) ;
        long     roundedTicks = (long) roundedUnits * unit.Ticks ;
        DateTime instance     = new DateTime( roundedTicks ) ;
        
        return instance ;
    }
    
}

Solution 7 - C#

My version

DateTime newDateTimeObject = oldDateTimeObject.AddMinutes(15 - oldDateTimeObject.Minute % 15);

As a method it would lock like this

public static DateTime GetNextQuarterHour(DateTime oldDateTimeObject)
{
    return oldDateTimeObject.AddMinutes(15 - oldDateTimeObject.Minute % 15);
}

and is called like that

DateTime thisIsNow = DateTime.Now;
DateTime nextQuarterHour = GetNextQuarterHour(thisIsNow);

Solution 8 - C#

Caution: the formula above is incorrect, i.e. the following:

DateTime RoundUp(DateTime dt, TimeSpan d)
{
    return new DateTime(((dt.Ticks + d.Ticks - 1) / d.Ticks) * d.Ticks);
}

should be rewritten as:

DateTime RoundUp(DateTime dt, TimeSpan d)
{
    return new DateTime(((dt.Ticks + d.Ticks/2) / d.Ticks) * d.Ticks);
}

Solution 9 - C#

A more verbose solution, that uses modulo and avoids unnecessary calculation.

public static class DateTimeExtensions
{
    public static DateTime RoundUp(this DateTime dt, TimeSpan ts)
    {
        return Round(dt, ts, true);
    }

    public static DateTime RoundDown(this DateTime dt, TimeSpan ts)
    {
        return Round(dt, ts, false);
    }

    private static DateTime Round(DateTime dt, TimeSpan ts, bool up)
    {
        var remainder = dt.Ticks % ts.Ticks;
        if (remainder == 0)
        {
            return dt;
        }

        long delta;
        if (up)
        {
            delta = ts.Ticks - remainder;
        }
        else
        {
            delta = -remainder;
        }

        return dt.AddTicks(delta);
    }
}

Solution 10 - C#

My DateTimeOffset version, based on Ramon's answer:

public static class DateExtensions
{
    public static DateTimeOffset RoundUp(this DateTimeOffset dt, TimeSpan d)
    {
        return new DateTimeOffset((dt.Ticks + d.Ticks - 1) / d.Ticks * d.Ticks, dt.Offset);
    }
}

Solution 11 - C#

Elegant?

dt.AddSeconds(900 - (x.Minute * 60 + x.Second) % 900)

Solution 12 - C#

This is a simple solution to round up to the nearest 1 minute. It preserves the TimeZone and Kind information of the DateTime. It can be modified to suit your own needs further (if you need to round to the nearest 5 minutes, etc).

DateTime dbNowExact = DateTime.Now;
DateTime dbNowRound1 = (dbNowExact.Millisecond == 0 ? dbNowExact : dbNowExact.AddMilliseconds(1000 - dbNowExact.Millisecond));
DateTime dbNowRound2 = (dbNowRound1.Second == 0 ? dbNowRound1 : dbNowRound1.AddSeconds(60 - dbNowRound1.Second));
DateTime dbNow = dbNowRound2;

Solution 13 - C#

You can use this method, it uses the specified date to ensure it maintains any of the globalization and datetime kind previously specified in the datetime object.

const long LNG_OneMinuteInTicks = 600000000;
/// <summary>
/// Round the datetime to the nearest minute
/// </summary>
/// <param name = "dateTime"></param>
/// <param name = "numberMinutes">The number minute use to round the time to</param>
/// <returns></returns>        
public static DateTime Round(DateTime dateTime, int numberMinutes = 1)
{
    long roundedMinutesInTicks = LNG_OneMinuteInTicks * numberMinutes;
    long remainderTicks = dateTime.Ticks % roundedMinutesInTicks;
    if (remainderTicks < roundedMinutesInTicks / 2)
    {
        // round down
        return dateTime.AddTicks(-remainderTicks);
    }

    // round up
    return dateTime.AddTicks(roundedMinutesInTicks - remainderTicks);
}

.Net Fiddle Test

If you want to use the TimeSpan to round, you can use this.

/// <summary>
/// Round the datetime
/// </summary>
/// <example>Round(dt, TimeSpan.FromMinutes(5)); => round the time to the nearest 5 minutes.</example>
/// <param name = "dateTime"></param>
/// <param name = "roundBy">The time use to round the time to</param>
/// <returns></returns>        
public static DateTime Round(DateTime dateTime, TimeSpan roundBy)
{            
    long remainderTicks = dateTime.Ticks % roundBy.Ticks;
    if (remainderTicks < roundBy.Ticks / 2)
    {
        // round down
        return dateTime.AddTicks(-remainderTicks);
    }

    // round up
    return dateTime.AddTicks(roundBy.Ticks - remainderTicks);
}

TimeSpan Fiddle

Solution 14 - C#

Solution from Ramon Smits with DateTime.MaxValue check:

DateTime RoundUp(DateTime dt, TimeSpan d) =>
    dt switch
    {
        var max when max.Equals(DateTime.MaxValue) => max,
        var v => new DateTime((v.Ticks + d.Ticks - 1) / d.Ticks * d.Ticks, v.Kind)
    };

Solution 15 - C#

You can try this:

string[] parts = ((DateTime)date_time.ToString("HH:mm:ss").Split(':');
int hr = Convert.ToInt32(parts[0]);
int mn = Convert.ToInt32(parts[1]);
int sec2min = (int)Math.Round(Convert.ToDouble(parts[2]) / 60.0, 0);

string adjTime = string.Format("1900-01-01 {0:00}:{1:00}:00.000",
(mn + sec2min > 59 ? (hr + 1 > 23 ? 0 : hr + 1) : hr),
 mn + sec2min > 59 ? 60 - mn + sec2min : mn + sec2min);

Each part (hr, min) must be incremented and adjusted to proper value for overflow, like 59 min > 00 then add 1 to hr, if it is 23, hr becomes 00. Ex. 07:34:57 is rounded to 07:35, 09:59:45 is rounded to 10:00, 23:59:45 is rounded to 00:00, which is the following day's time.

Categories
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