SAS : INTCK Function with Examples

The INTCK is one of the most important date function that is used to calculate the difference between two dates, two times or two datetime values.

The following is a list of common real-world examples where INTCK is used -
1. Calculation of individual's age
2. Tenure of an employee with company
3. Customer's tenure with the organization
4. Number of working days
5. Number of hours spent on a particular course
6. Number of quarterly payments paid

INTCK - Syntax

The syntax of INTCK is defined below -
INTCK(date-or-time-interval, start-date-or-time, end-date-or-time, [method])
1. date-or-time-interval : Date or time period needs to be defined in the first parameter. For eg. MONTH, YEAR, QTR, WEEK, HOUR, MINUTE etc. Specify period in single quotes

2. start-date-or-time : Starting date or time to calculate the number of periods.

3. end-date-or-time : End date or time to calculate the number of periods.

4. method : Optional Parameter. Method to calculate the difference. Methods are 'CONTINUOUS' or 'DISCRETE'. By default, it is DISCRETE.

Simplest Example of INTCK

Calculate the number of years between two dates. In this case, two dates are 01JAN2015 and 01JAN2017.
data temp;
date1 = '01JAN2015'd;
date2 = '01JAN2017'd;
no_of_years  = intck ('YEAR', date1, date2);
format date1 date2 date9.;
proc print data = temp;
run;
The 'YEAR' keyword tells SAS to calculate the number of intervals between dates in terms of year. Since 01JAN2015 is a starting date, it is specified in the INTCK function before 01JAN2017. The FORMAT statement is used to display datevalues in date format when we print our results.

The output is shown below -
 SAS : INTCK Function

Other alias of year - 'YEARS' and 'YR'-
no_of_years  = intck ('YEARS', date1, date2)
no_of_years  = intck ('YR', date1, date2)

SAS INTCK Examples

Like calculation of years, we can use other intervals such as semiyear, quarter, month, week, day. The examples of these intervals are displayed below -
data temp;
date1 = '01JAN2015'd;
date2 = '01JAN2017'd;
no_of_years  = intck ('YEAR', date1, date2);
no_of_semiyears  = intck ('SEMIYEAR', date1, date2);
no_of_quarters  = intck ('QUARTER', date1, date2);
no_of_months  = intck ('MONTH', date1, date2);
no_of_weeks  = intck ('WEEK', date1, date2);
no_of_days  = intck ('DAY', date1, date2);
format date1 date2 date9.;
proc print data = temp noobs;
run;
 INTCK Examples

Custom Intervals

Suppose you are asked to calculate the number of 4 months interval between two dates -
data temp;
date1 = '01JAN2015'd;
date2 = '01JAN2017'd;
no_of_4months  = intck ('MONTH4', date1, date2);
run;

The MONTH4 interval implies interval is of 4 months. It is equal to the number of months divided by 4. Don't confuse it with QUARTERS. QUARTERS is equal to interval of 3 months. Remember 4 Quarters in an year.

Result : no_of_4months = 6
Similarly, we can use the custom intervals in YEAR, QUARTER and other periods. For example, 'YEAR2' tells SAS the interval is of 2 years. It would return 1 for the above mentioned dates.

Set Starting Point for Calculation
data temp;
date1 = '31JAN2015'd;
date2 = '31DEC2016'd;
diff  = intck ('YEAR', date1, date2);
diff2  = intck ('YEAR.3', date1, date2);
format date1 date2 date9.;
proc print;
run;
Function Result
intck ('YEAR', '31JAN2015'd, '31DEC2016'd) 1
intck ('YEAR.3', '31JAN2015'd, '31DEC2016'd) 2

How it works :
1. intck ('YEAR', date1, date2) - It checks number of times first of January appears as first of january is set as a starting point by default. The variable diff returns 1 as it includes only 01JAN 2016.
2. intck ('YEAR.3', date1, date2) - It checks number of times first of March appears as YEAR.3 refers to the period starting from 1st of March to end of February next year. The variable diff2 returns 2 as it includes 01 March 2015 and 01March 2016.

Is it a month difference?

INTCK says there is a month difference between 25OCT2016 and 03NOV2016. But there is no month difference between 01OCT2016 and 31OCT2016. How?
data temp;
month1= intck('month', '25OCT2016'd, '03NOV2016'd);
month2= intck('month', '01OCT2016'd, '31OCT2016'd);
proc print;
run;

Function Result
intck ('month', '25OCT2016'd, '03NOV2016'd) 1
intck ('month', '01OCT2016'd, '31OCT2016'd) 0
INTCK checks whether the first day of the month lies with in the range. In the first case, 01 November falls between October 25 and November 03 so it returns 1. In the second case, it returns 0 as 01 November does not fall between 01OCT2016 and 31OCT2016.

How to correct it?

Add one more parameter at end of INTCK function. In the parameter, specify 'C' which refers to continuous method for calculation.
data temp;
month1= intck('month', '25OCT2016'd, '03NOV2016'd, 'C');
proc print;
run;
The above function returns 0.

The CONTINUOUS method calculates continuous time from the start-of-period date specified in the second parameter of INTCK function.

Calculating Weekdays

Suppose you are asked to calculate the number of weekdays -
data eg;
weekdays = intck('WEEKDAY', '11DEC2016'd ,'18DEC2016'd);
proc print;
run;
It returns 5. In this case, saturday and sunday are considered weekends and excluding from the calculation.

Define 6 days working

If you need to calculate number of working days between 2 dates considering 6 weekdays -
data eg;
weekdays = intck('WEEKDAY1W', '11DEC2016'd ,'18DEC2016'd);
proc print;
run;
WEEKDAY1W implies sunday as weekend (1=Sunday, 2= MONDAY... 7=Saturday)

Set Custom Weekends
data eg;
weekdays = intck('WEEKDAY24W', '11DEC2016'd ,'16DEC2016'd);
proc print;
run;
WEEKDAY24W means MONDAY and WEDNESDAY are weekends. The above function returns 3

Calculate between Datetime values

Suppose you need to calculate hours, minutes and seconds between two datetime values.
data temp2;
hours=intck('hour','01jan2016:10:50:00'dt,'01jan2016:11:55:00'dt);
minutes=intck('minute','01jan2016:10:50:00'dt,'01jan2016:11:55:00'dt);
seconds=intck('second','01jan2016:10:50:00'dt,'01jan2016:11:55:00'dt);
proc print noobs;
run;
 Time Calculation
Result - 1 hour, 65 minutes and 3900 seconds

Time Difference
data temp3;
hours=intck('hour','12:00:00't, '23:05:00't);
minutes=intck('minute','12:00:00't,'23:05:00't);
seconds=intck('second','12:00:00't,'23:05:00't);
proc print noobs;
run;
Result : 11 hours 665 minutes 39900 seconds
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Deepanshu founded ListenData with a simple objective - Make analytics easy to understand and follow. He has over 10 years of experience in data science. During his tenure, he has worked with global clients in various domains like Banking, Insurance, Private Equity, Telecom and Human Resource.

23 Responses to "SAS : INTCK Function with Examples"
1. Thank u so much Deepanshu Bhalla. Awesome Explanation.
I have a doubt,
In the Set Custom Weekends part the differnce b/w the dates 11DEC2016 and 16DEC2016 is '6 days'. So on passing the function 'WEEKDAY24W' it will consider Monday and Wednesday as weekends, so the number of weekdays must be
(6-2) = 4 right? But y is it returning 3? Can u please explain?

1. It is because the difference between two days are 5 (not including 16DEC). See the code below -
data eg;
days = intck('DAY', '11DEC2016'd ,'16DEC2016'd);
proc print;
run;

2. Thank You got it. :)

3. Calculate the months,weeks and days separately since the coupon expiry date (from current date to 31-mar-2014)
if there is given coupon expiry date starting from 20feb2014,then how to calculate such type of problem??explain plz

2. Hi thank you for your help. I just have one question - When I am trying to find out the no of weeks between 01/11/2014 and 01/03/2015, it is showing 51 when the answer should be 52. Can you please suggest why this is so?

1. Week start from Sunday. As you are taking date which is starting from Saturday, it is calculating Saturday as 1 week.
try to use continuous method for calculation.

3. Great explaination. Thank you

4. Hi Deepanshu, when i m using "C" in intck fn sas hitting error saying "intck function call has too many arguments". please explain.

1. "c" method is not supported in older version.

5. App_Yr_Mon = intnx('month',disbursed_dt,0,'E').....What does E stand for ?

1. E stands for 'ending' usually returns last day of the month, etc. Don't confuse intck with intnx function. It's a different function at all.

6. Hi
data x;
input name\$ date1 date2 date10.;
x1=intck('Month',date1,date2);
datalines;
neha '01DEC2018'd '01DEC2018'd
Gupta '01DEC2018'd '11DEC2018'd
Goyal '01DEC2018'd '10DEC2018'd
;
Run;

Could you please guide me what is the wrong with this code?

1. Hello

try this :

data x;
input name\$ date1 date10. date2 date10.;
x1=intck('Month',date1,date2);
format date1 date2 date10.;
datalines;
neha 01DEC2018 01DEC2018
Gupta 01DEC2018 11DEC2018
Goyal 01DEC2018 10DEC2018
;
Run;

7. Can you please show any example which have multiple dates in dataset
Like i have a dataset which have 10 participant. Date of birth for all employees are different and i want to know how old they are on 12/30/2017 date.

8. Calculate the months,weeks and days separately since the coupon expiry date (from current date to 31-mar-2014)
if there is given coupon expiry date starting from 20feb2014,then how to calculate such type of problem??explain plz

9. In the event that you looking for means of how to find out how old someone is then you will see ideas you could look at here. To retrieve such information you need to think of all of the areas where people give their arrival date information along with these places must be accessible during online searches. You need to try age calculator through that you can determine your age instantly.I highly suggested you this age calculator through which you can calculate your age in Years, months, Days, weeks, hours, minutes and seconds.

10. what is the use of noobs?

1. It will not show observations no. as first variable.

2. it supresses the number of obesevatin

11. I love this site as quick correct responses to questions asked !!

12. how week is calculated between two dates if i have 19DEC2019 and 24DEC2019 then sas says its 1 week but 06JAN2020 and 10JAN2020 sas says week is 0 how? please tell me logic

13. can anyone write the code to find the differences between those dates.

data arjun;
input startday:\$10. endday:\$10. ;
datalines;
11jan2012 30jan2012
12jan2012 30jan2012
11mar2012 30mar2012
12apr2012 30may2012
31mar2022 15may2022
31mar2022 25may2022
;
run;

14. Thank you so much Deepanshu Bhalla. Great explanation. I just have a question: I want to use intck function for data deduplication. I need to remove obs for the same person with different testing dates <12 months and keep the obs with > 12 months difference.

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