Number of days in particular month of particular year?

Question

How to know how many days has particular month of particular year?

String date = "2010-01-19";
String[] ymd = date.split("-");
int year = Integer.parseInt(ymd[0]);
int month = Integer.parseInt(ymd[1]);
int day = Integer.parseInt(ymd[2]);
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.YEAR,year);
calendar.set(Calendar.MONTH,month);
int daysQty = calendar.getDaysNumber(); // Something like this

FYI, the terribly troublesome old date-time classes such as [`java.util.Date`](https://docs.oracle.com/javase/10/docs/api/java/util/Date.html), [`java.util.Calendar`](https://docs.oracle.com/javase/10/docs/api/java/util/Calendar.html), and `java.text.SimpleDateFormat` are now [legacy](https://en.wikipedia.org/wiki/Legacy_system), supplanted by the [*java.time*](https://docs.oracle.com/javase/10/docs/api/java/time/package-summary.html) classes built into Java 8 and later. See [*Tutorial* by Oracle](https://docs.oracle.com/javase/tutorial/datetime/TOC.html). — Basil Bourque, Aug 03 '18 at 19:18

score 443 · Accepted Answer · edited Aug 03 '18 at 19:17

443

Java 8 and later

@Warren M. Nocos. If you are trying to use Java 8's new Date and Time API, you can use java.time.YearMonth class. See Oracle Tutorial.

// Get the number of days in that month
YearMonth yearMonthObject = YearMonth.of(1999, 2);
int daysInMonth = yearMonthObject.lengthOfMonth(); //28

Test: try a month in a leap year:

yearMonthObject = YearMonth.of(2000, 2);
daysInMonth = yearMonthObject.lengthOfMonth(); //29

Java 7 and earlier

Create a calendar, set year and month and use getActualMaximum

int iYear = 1999;
int iMonth = Calendar.FEBRUARY; // 1 (months begin with 0)
int iDay = 1;

// Create a calendar object and set year and month
Calendar mycal = new GregorianCalendar(iYear, iMonth, iDay);

// Get the number of days in that month
int daysInMonth = mycal.getActualMaximum(Calendar.DAY_OF_MONTH); // 28

Test: try a month in a leap year:

mycal = new GregorianCalendar(2000, Calendar.FEBRUARY, 1);
daysInMonth= mycal.getActualMaximum(Calendar.DAY_OF_MONTH);      // 29

edited Aug 03 '18 at 19:17

Basil Bourque

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answered Jan 20 '12 at 11:08

Hemant Metalia

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How to do this on Java 8's new Date and Time API? – Warren Nocos Nov 09 '15 at 11:36
2

@WarrenM.Nocos sorry for late response, but i wasnt active these months. please check the edit for the solution for java 8. – Hemant Metalia Jan 20 '16 at 06:55
1

As for prior to Java 8… Much of the *java.time* functionality is back-ported to Java 6 & Java 7 in the [***ThreeTen-Backport***](http://www.threeten.org/threetenbp/) project. Further adapted for earlier Android in the [***ThreeTenABP***](https://github.com/JakeWharton/ThreeTenABP) project. See [*How to use ThreeTenABP…*](http://stackoverflow.com/q/38922754/642706). – Basil Bourque Aug 03 '18 at 19:20

score 49 · Answer 2 · edited Nov 11 '15 at 19:19

Code for java.util.Calendar

If you have to use java.util.Calendar, I suspect you want:

int days = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);

Code for Joda Time

Personally, however, I'd suggest using Joda Time instead of java.util.{Calendar, Date} to start with, in which case you could use:

int days = chronology.dayOfMonth().getMaximumValue(date);

Note that rather than parsing the string values individually, it would be better to get whichever date/time API you're using to parse it. In java.util.* you might use SimpleDateFormat; in Joda Time you'd use a DateTimeFormatter.

score 31 · Answer 3 · answered Jan 20 '12 at 11:09

31

You can use Calendar.getActualMaximum method:

Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.YEAR, year);
calendar.set(Calendar.MONTH, month);
int numDays = calendar.getActualMaximum(Calendar.DATE);

answered Jan 20 '12 at 11:09

Aleks G

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score 28 · Answer 4 · edited Mar 02 '17 at 05:03

28

`java.time.LocalDate`

From Java 1.8, you can use the method lengthOfMonth on java.time.LocalDate:

LocalDate date = LocalDate.of(2010, 1, 19);
int days = date.lengthOfMonth();

edited Mar 02 '17 at 05:03

Basil Bourque

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answered Mar 07 '16 at 17:54

Alexandre DuBreuil

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Shl · Answer 5 · 2022-11-07T09:14:35.667

14

This is the mathematical way:

For year (e.g. 2012), month (1 to 12):

int daysInMonth = month !== 2 ? 
  31 - (((month - 1) % 7) % 2) : 
  28 + (year % 4 == 0 ? 1 : 0) - (year % 100 == 0 ? 1 : 0) + (year % 400 == 0 ? 1 : 0)

edited Nov 07 '22 at 09:14

answered Oct 06 '17 at 11:45

Shl

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score 7 · Answer 6 · edited Jan 05 '22 at 23:48

7

if (month == 4 || month == 6 || month == 9 || month == 11) {
   daysInMonth = 30;
} else if (month == 2) {
    daysInMonth = (leapYear) ? 29 : 28;
else { 
    daysInMonth = 31;
}

edited Jan 05 '22 at 23:48

OneCricketeer

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answered Mar 02 '13 at 08:25

zoidbot

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Calendar c = Calendar.getInstance();c.set(Calendar.DAY_OF_MONTH, c.getActualMaximum(Calendar.DAY_OF_MONTH)); // you can set the year before you get the actual maximum coz they might not be the same. ie feb of 2011 and 2012 is not same length (leap year) – Rose Jul 10 '13 at 22:02

score 4 · Answer 7 · edited Jun 26 '19 at 10:23

4

I would go for a solution like this:

int monthNr = getMonth();
final Month monthEnum = Month.of(monthNr);
int daysInMonth;
if (monthNr == 2) {
    int year = getYear();
    final boolean leapYear = IsoChronology.INSTANCE.isLeapYear(year);
    daysInMonth = monthEnum.length(leapYear);
} else {
    daysInMonth = monthEnum.maxLength();
}

If the month isn't February (92% of the cases), it depends on the month only and it is more efficient not to involve the year. This way, you don't have to call logic to know whether it is a leap year and you don't need to get the year in 92% of the cases. And it is still clean and very readable code.

edited Jun 26 '19 at 10:23

adiga

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answered Jun 26 '19 at 10:11

Stefan Mondelaers

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I’d prefer to leave the whole logic to a proven library method — I think you’re optimizing very prematurely, and the library methods aren’t that inefficient. Still upvoted for the use of the modern java.time. – Ole V.V. Jun 26 '19 at 10:52
@OleV.V. True, in many cases leaving the optimization to a proven library can be better. But, in this case, existing libraries will require to pass a month and year. So that means I need to do whatever it takes to get the year anyway even if the method won't use the value in 92% of the cases. So, that's a part it can't optimize for me. My reasoning is similar to the reason why you shouldn't do a method call to get a value to be passed to a logger which might be disabled. No way that the logger can optimize that. – Stefan Mondelaers Jun 26 '19 at 11:27

score 3 · Answer 8 · answered Aug 14 '18 at 09:23

3

Simple as that,no need to import anything

public static int getMonthDays(int month, int year) {
    int daysInMonth ;
    if (month == 4 || month == 6 || month == 9 || month == 11) {
        daysInMonth = 30;
    }
    else {
        if (month == 2) {
            daysInMonth = (year % 4 == 0) ? 29 : 28;
        } else {
            daysInMonth = 31;
        }
    }
    return daysInMonth;
}

answered Aug 14 '18 at 09:23

Ajay Chauhan

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This is OK, if you don't need historical dates or dates in far future. For February of years which are multiples of 100 but not multiples of 400, it will be wrong. But I agree, in most applications this will do and it is efficient. – Stefan Mondelaers Jun 26 '19 at 11:35

score 2 · Answer 9 · answered Aug 29 '17 at 04:37

In Java8 you can use get ValueRange from a field of a date.

LocalDateTime dateTime = LocalDateTime.now();

ChronoField chronoField = ChronoField.MONTH_OF_YEAR;
long max = dateTime.range(chronoField).getMaximum();

This allows you to parameterize on the field.

score 2 · Answer 10 · edited Mar 04 '19 at 08:27

Lets make it as simple if you don't want to hardcode the value of year and month and you want to take the value from current date and time:

Date d = new Date();
String myDate = new SimpleDateFormat("dd/MM/yyyy").format(d);
int iDayFromDate = Integer.parseInt(myDate.substring(0, 2));
int iMonthFromDate = Integer.parseInt(myDate.substring(3, 5));
int iYearfromDate = Integer.parseInt(myDate.substring(6, 10));

YearMonth CurrentYear = YearMonth.of(iYearfromDate, iMonthFromDate);
int lengthOfCurrentMonth = CurrentYear.lengthOfMonth();
System.out.println("Total number of days in current month is " + lengthOfCurrentMonth );

score 2 · Answer 11 · edited May 20 '19 at 10:45

2

// 1 means Sunday ,2 means Monday .... 7 means Saturday
//month starts with 0 (January)

MonthDisplayHelper monthDisplayHelper = new MonthDisplayHelper(2019,4);
int numbeOfDaysInMonth = monthDisplayHelper.getNumberOfDaysInMonth();

edited May 20 '19 at 10:45

Ommadawn

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answered May 20 '19 at 09:52

user11527435

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It's worth to note that it's for Android (`android.util.MonthDisplayHelper`) – barbsan May 20 '19 at 10:22

score 1 · Answer 12 · edited Jun 26 '19 at 10:24

1

Following method will provide you the no of days in a particular month

public static int getNoOfDaysInAMonth(String date) {
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    return (cal.getActualMaximum(Calendar.DATE));
}

edited Jun 26 '19 at 10:24

adiga

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answered Jun 29 '16 at 13:15

Tanmay kumar shaw

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whats the format of the string date should be passed ? – Mahmoud Ayman Mar 19 '21 at 08:01

score 0 · Answer 13 · answered Sep 10 '14 at 12:05

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

/*
 * 44. Return the number of days in a month
 * , where month and year are given as input.
 */
public class ex44 {
    public static void dateReturn(int m,int y)
    {
        int m1=m;
        int y1=y;
        String str=" "+ m1+"-"+y1;
        System.out.println(str);
        SimpleDateFormat sd=new SimpleDateFormat("MM-yyyy");

        try {
            Date d=sd.parse(str);
            System.out.println(d);
            Calendar c=Calendar.getInstance();
            c.setTime(d);
            System.out.println(c.getActualMaximum(Calendar.DAY_OF_MONTH));
        } catch (ParseException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }
    public static void main(String[] args) {
dateReturn(2,2012);


    }

}

What value does this answer provide over the existing and accepted answers? Also, please add some explanation or narrative along with your code. StackOverflow is more than a snippet library. — Basil Bourque, Sep 10 '14 at 16:29

score 0 · Answer 14 · edited Jun 26 '19 at 10:24

You can use Calendar.getActualMaximum method:

Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.YEAR, year);
calendar.set(Calendar.MONTH, month-1);
int numDays = calendar.getActualMaximum(Calendar.DATE);

And month-1 is Because of month takes its original number of month while in method takes argument as below in Calendar.class

public int getActualMaximum(int field) {
   throw new RuntimeException("Stub!");
}

And the (int field) is like as below.

public static final int JANUARY = 0;
public static final int NOVEMBER = 10;
public static final int DECEMBER = 11;

score 0 · Answer 15 · edited Nov 14 '17 at 07:59

0

public class Main {

    private static LocalDate local=LocalDate.now();
    public static void main(String[] args) {

            int month=local.lengthOfMonth();
            System.out.println(month);

    }
}

edited Nov 14 '17 at 07:59

jHilscher

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answered Nov 14 '17 at 06:58

Nodirbek Hasanboev

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Add some explanations as well. – BlackBeard Nov 14 '17 at 06:59
1

Welcome to Stack Overflow! While this code snippet may be the solution, [including an explanation](//meta.stackexchange.com/questions/114762/explaining-entirely-‌code-based-answers) really helps to improve the quality of your post. Remember that you are answering the question for readers in the future, and those people might not know the reasons for your code suggestion. – yivi Nov 14 '17 at 09:40

xingbin · Answer 16 · 2018-04-29T12:34:24.340

0

The use of outdated Calendar API should be avoided.

In Java8 or higher version, this can be done with YearMonth.

Example code:

int year = 2011;
int month = 2;
YearMonth yearMonth = YearMonth.of(year, month);
int lengthOfMonth = yearMonth.lengthOfMonth();
System.out.println(lengthOfMonth);

edited Apr 29 '18 at 12:34

answered Apr 29 '18 at 11:41

xingbin

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`Call requires API level 26 (current min is 21): java.time.YearMonth#lengthOfMonth` – Vlad May 04 '18 at 14:58

score 0 · Answer 17 · answered Nov 17 '19 at 22:54

An optimal and performant variance:

public static int daysInMonth(int month, int year) {
    if (month != 2) {
        return 31 - (month - 1) % 7 % 2;
    }
    else {
        if ((year & 3) == 0 && ((year % 25) != 0 || (year & 15) == 0)) { // leap year
            return 29;
        } else {
            return 28;
        }
    }
}

For more details on the leap algorithm check here

score 0 · Answer 18 · answered Nov 26 '20 at 14:11

0

Number of days in particular year - Java 8+ solution

Year.now().length()

answered Nov 26 '20 at 14:11

Tionio

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Does not address the Question. The Question is about length of month, not year. And the `.length()` method has been covered multiple times already in other Answers. – Basil Bourque Nov 27 '20 at 05:39

score 0 · Answer 19 · edited Aug 29 '21 at 10:41

An alternative solution is to use a Calendar object. Get the current date and set the day so it is the first of the month. Then add one month and take away one day to get the last day of the current month. Finally fetch the day to get the number of days in the month.

Calendar today = getInstance(TimeZone.getTimeZone("UTC"));

Calendar currMonthLastDay = getInstance(TimeZone.getTimeZone("UTC"));
currMonthLastDay.clear();
currMonthLastDay.set(YEAR, today.get(YEAR));
currMonthLastDay.set(MONTH, today.get(MONTH));
currMonthLastDay.set(DAY_OF_MONTH, 1); 
currMonthLastDay.add(MONTH, 1);
currMonthLastDay.add(DAY_OF_MONTH, -1);

Integer daysInMonth = currMonthLastDay.get(DAY_OF_MONTH);

score -1 · Answer 20 · edited Jun 26 '19 at 10:24

-1

String date = "11-02-2000";
String[] input = date.split("-");
int day = Integer.valueOf(input[0]);
int month = Integer.valueOf(input[1]);
int year = Integer.valueOf(input[2]);
Calendar cal=Calendar.getInstance();
cal.set(Calendar.YEAR,year);
cal.set(Calendar.MONTH,month-1);
cal.set(Calendar.DATE, day);
//since month number starts from 0 (i.e jan 0, feb 1), 
//we are subtracting original month by 1
int days = cal.getActualMaximum(Calendar.DAY_OF_MONTH);
System.out.println(days);

edited Jun 26 '19 at 10:24

adiga

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answered Sep 24 '14 at 07:07

Naga Budigam

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No need to answer to a question that is already accepted, until that answer invalid any how. – Deepak Sep 24 '14 at 07:29

score -1 · Answer 21 · edited Mar 04 '19 at 08:45

This worked fine for me.

This is a Sample Output

import java.util.*;

public class DaysInMonth { 

    public static void main(String args []) { 

        Scanner input = new Scanner(System.in); 
        System.out.print("Enter a year:"); 

        int year = input.nextInt(); //Moved here to get input after the question is asked 

        System.out.print("Enter a month:"); 
        int month = input.nextInt(); //Moved here to get input after the question is asked 

        int days = 0; //changed so that it just initializes the variable to zero
        boolean isLeapYear = (year % 4 == 0 && year % 100 != 0) || (year % 400 == 0); 

        switch (month) { 
            case 1: 
                days = 31; 
                break; 
            case 2: 
                if (isLeapYear) 
                    days = 29; 
                else 
                    days = 28; 
                break; 
            case 3: 
                days = 31; 
                break; 
            case 4: 
                days = 30; 
                break; 
            case 5: 
                days = 31; 
                break; 
            case 6: 
                days = 30; 
                break; 
            case 7: 
                days = 31; 
                break; 
            case 8: 
                days = 31; 
                break; 
            case 9: 
                days = 30; 
                break; 
            case 10: 
                days = 31; 
                break; 
            case 11: 
                days = 30; 
                break; 
            case 12: 
                days = 31; 
                break; 
            default: 
                String response = "Have a Look at what you've done and try again";
                System.out.println(response); 
                System.exit(0); 
        } 

        String response = "There are " + days + " Days in Month " + month + " of Year " + year + ".\n"; 
        System.out.println(response); // new line to show the result to the screen. 
    } 
} //abhinavsthakur00@gmail.com

score -1 · Answer 22 · edited Nov 13 '18 at 19:02

String  MonthOfName = "";
int number_Of_DaysInMonth = 0;

//year,month
numberOfMonth(2018,11); // calling this method to assign values to the variables MonthOfName and number_Of_DaysInMonth 

System.out.print("Number Of Days: "+number_Of_DaysInMonth+"   name of the month: "+  MonthOfName );

public void numberOfMonth(int year, int month) {
    switch (month) {
        case 1:
            MonthOfName = "January";
            number_Of_DaysInMonth = 31;
            break;
        case 2:
            MonthOfName = "February";
            if ((year % 400 == 0) || ((year % 4 == 0) && (year % 100 != 0))) {
                number_Of_DaysInMonth = 29;
            } else {
                number_Of_DaysInMonth = 28;
            }
            break;
        case 3:
            MonthOfName = "March";
            number_Of_DaysInMonth = 31;
            break;
        case 4:
            MonthOfName = "April";
            number_Of_DaysInMonth = 30;
            break;
        case 5:
            MonthOfName = "May";
            number_Of_DaysInMonth = 31;
            break;
        case 6:
            MonthOfName = "June";
            number_Of_DaysInMonth = 30;
            break;
        case 7:
            MonthOfName = "July";
            number_Of_DaysInMonth = 31;
            break;
        case 8:
            MonthOfName = "August";
            number_Of_DaysInMonth = 31;
            break;
        case 9:
            MonthOfName = "September";
            number_Of_DaysInMonth = 30;
            break;
        case 10:
            MonthOfName = "October";
            number_Of_DaysInMonth = 31;
            break;
        case 11:
            MonthOfName = "November";
            number_Of_DaysInMonth = 30;
            break;
        case 12:
            MonthOfName = "December";
            number_Of_DaysInMonth = 31;
    }
}

Number of days in particular month of particular year?

22 Answers22

Java 8 and later

Java 7 and earlier

Code for java.util.Calendar

Code for Joda Time

`java.time.LocalDate`

Linked

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