Today is February 29th, and that means, this year we have one more day to be awesome. So lets celebrate it in Excel style!
Lets learn 14 different ways to tell if an year is leap year, using Excel Formulas.
Why 14? because, we are awesome like that.
Why 14 methods to just find the year in cell D4 is leap year or not? Because, we all know that by learning different ways to solve a problem, we become smarter, more awesome and have more fun. So lets roll.
Before we start..,
Since all the 14 methods rely on certain calculations, I have created some names. See below:
All the names are self-explanatory, except the febDays. So lets take a look at it.
febDays formula
For one of the methods, we need to have all the dates in February in a list. If we want the first of Feb as a date, we can use =DATE(year,2,1). But we want all dates in February. That means, we need to use a list (array) in third parameter of DATE like this:
=DATE(year,2,{1,2,3,4,….,28,29})
Instead of typing all the 28/29 numbers, we can use ROW formula to generate these, like:
=ROW($A$1:$A$29) would give me a numbers from 1 thru 29.
But the problem is in many years Feb has only 28 days, and for rest, it has 29 days. So we modify the second part of row formula and use the last DAY of the Feb, like this:
=ROW($A$1: INDEX($A$1:$A$29,DAY(EOMONTH(feb1st,0))))
To get the last day of a month, we use = DAY(EOMONTH(1st date, 0))
I think you can put the rest of pieces together to solve this puzzle.
Moving on,
#1 – The year has 366 days
This is the obvious one. We use =DATE(year+1,1,1)-jan1st=366 to check if there are 366 days between January 1st of next year and this year.
#2 – February 29th is not March 1st
Because in Excel all dates are numbers, when we use a formula like =DATE(2011,2,29), Excel gives us the date of March 1st, even though we wanted 29th Day of February in 2011. So a simple leap year check is to see if February 29 is March 1st or not!
=DATE(year,2,29)<>mar1st
#3 – February has 29 days
This is another obvious test. In a leap year, February has 29 days. So=DAY(EOMONTH(feb1st,0))=29 will be true for leap years.
#4 – February 1st and March 1st are not on same day of week
In non leap years, Feb has 28 days (a multiple of 7), so both Feb and March start on same day of week. So, =WEEKDAY(feb1st)<>WEEKDAY(mar1st) will be TRUE for leap years.
#5 – Adding 365 to January 1st does not change year
Well, that is obvious too. =YEAR(jan1st)=YEAR(jan1st+365) is TRUE for leap years.
#6 – 30th Day of February is March 1st
If an year is leap year, 30th day of February [DATE(year,2,30)] is same as March 1st. So, =DATE(year,2,30)=mar1st is TRUE for leap years.
#7 – 0th Day of March is Feb 29th
In real world there is no zeroth day for any month. But in Excel, since all dates are numbers, 0th day refers to last day of previous month. So, =DAY(DATE(year,3,0))=29 will be TRUE in leap years.
#8 – April 1st and January 1st are on same day of week
In leap years, there are 91 days between January 1st and April 1st. And since 91 is a multiple of 7, both April 1st and January 1st start on same day of week. Hence, =WEEKDAY(jan1st)=WEEKDAY(apr1st) will be true for leap years.
#9 – Only 2 more months start on same day of week as January
In leap years, both April and July start on same day of week as January. (Where as in non-leap years, Only October starts on same day of week as Jan).
To test this, we will of course use the SUMPRODUCT. like this:
=SUMPRODUCT(–(WEEKDAY(DATE(year,ROW($A$2:$A$12),1))=WEEKDAY(jan1st)))=2
The portion WEEKDAY(DATE(year,ROW($A$2:$A$12),1)) gives all the first day of weeks from February to December. And then we just check how many of these are same as January 1st’s week day.
#10 – Next year’s February 1st and this year’s February 2nd are NOT on same day of week
In non-leap years, there are 364 days between February 2nd and next year’s February 1st. Since 364 is a multiple of 7, both of these days are on same day of week. Which is not the case in leap years (as the difference becomes 365). So, =WEEKDAY(feb1st+1)<>WEEKDAY(EDATE(feb1st,12)) will be TRUE for leap years.
#11 – February 1st’s day of week occurs 5 times in that month
This a bit tricky to test, but then again we have SUMPRODUCT. So, =SUMPRODUCT(–(WEEKDAY(febDays)=WEEKDAY(feb1st)))=5 will be TRUE for leap years. The name febDays has all dates in February. I think the rest is easy to understand.
#12 – February starts and ends on same day of week
29 days means both 1st and 29 are on same weekday. So, =WEEKDAY(feb1st)=WEEKDAY(EOMONTH(feb1st,0)) will be true for leap years.
#13 – Spreadsheet day (October 17) and February 1st are on same day of week
Debra, who is a well known Excel blogger & author started the whole spreadsheet day thing. She says, we should celebrate October 17 as spreadsheet day. I love that idea, mainly because, it is just 3 days before my birthday and I like celebrations. And I also like Excel 🙂 So blame her if you do not like this way of testing for leap years.
In leap years, there are 259 days between February 1st and October 17. And since 259 is a multiple of 7 (and 37), we know that they are both on same day of week. So, =WEEKDAY(feb1st)=WEEKDAY(DATE(year,10,17)) is true for leap years.
#14 – Finally, the year is divisible by 4 and if it is divisible by 100, then also by 400
Finally, we are going to test the whole “an year is leap year if it is divisible by 4 and if it is divisible by 100, then it is also divisible by 400” thing. This is a slightly tricky one to test. The formula, =((MOD(year,4)=0)*((MOD(year,100)<>0)+(MOD(year,400)=0))=1) will be TRUE for leap years and false for non-leap years.
Download Leap Year Test Workbook
Click here to download the workbook with all these 14 examples. Play with the formulas, named ranges to understand these techniques.
How do you check it is a leap year?
If you are working and you get paid on first day of a month, then one clear way of knowing leap year is that you get your salary one day later. Other than this, what method would you use to find if an year is leap year. Go ahead and be creative. Share your ideas and formulas using comments. Next leap day is 4 years away. Go
Want to learn how to Dates & Times in Excel – Read these:
If you deal with data that has a lot of date / time stuff, then understanding various Excel features in this area is a must. Read below pages to learn more.
- 10 tips on working with dates & times in Excel
- Calculate difference between 2 dates
- Find thanksgiving day for any year
- Check if 2 ranges of dates overlap
- Rolling months in Excel
- How to convert text to dates
- Even more on Excel dates & times
Want to master Date & Other Excel Formulas?
If you want to learn how various formulas in this post work and know more about everyday Excel formulas, please consider joining my Excel Formula crash course. It has detailed video tutorials on more than 40 everyday Excel formulas and teaches you all the powerful techniques to become a formula ninja.
28 Responses to “Team To Do Lists – Project Tracking Tools using Excel [Part 2 of 6]”
[...] & tracking a project plan using Gantt Charts Team To Do Lists - Project Tracking Tools Part 3: Preparing a project time line [upcoming] Part 4: Time sheets and Resource management [...]
the templates are great (I bought the combo).
What I'm missing is a way to have the project gantt chart and reporting with the data per resource, in such a way that I can also show the occupation per resource on an extended gantt chart.
So with hours entered per person per project or sub-activity, to show a gantt chart of how many hours/days a person spent on which project (or plans to spend).
[...] from: Team To Do Lists - Project Tracking Tools using Excel [Part 2 of 6] 25 Jun 09 | [...]
Hi Chandoo,
Funny I have a post on the value of MS project lined up which I will post when the current monster project I'm working on finishes and I get some free time!
I'm not sure this would help with any of the projects I've worked on, closing down a to do list seems like more effort than it's worth, but it might be useful for some things. I guessing it doesn't, but does the time stamp not update when you recalculate the work book?
keep up the good work!
Ross
@Ross.. Thanks for sharing your ideas... I think to do lists are a great way to keep up with project activities and ensure accountability from individual team members, when they are implemented right.
"I guessing it doesn’t, but does the time stamp not update when you recalculate the work book?"
Your guess is right. When you change the calculation mode to "iterative", excel takes care of the nittygritties and retains older values in circular references in formulas.
[...] Project Management in Excel [New Series] - Gantt Charts | To Do Lists [...]
[...] & tracking a project plan using Gantt Charts Team To Do Lists - Project Tracking Tools Project Status Reporting - Create a Timeline to display milestones Part 4: Time sheets and Resource [...]
Hi Chandoo,
The template give me lot of convenience to monitor the thing to do. It simple. Thank You
[...] & tracking a project plan using Gantt Charts Team To Do Lists - Project Tracking Tools Project Status Reporting - Create a Timeline to display milestones Part 4: Time sheets and Resource [...]
[...] make sure you have read the first 4 parts of the series - Making gantt charts [project planning], team todo lists [project tracking], project time lines chart [reporting] and Timesheets and Resource Management using Excel. Also [...]
Chandoo,
I really do not see any befit to this function in Excel unless it was somehow tied into some other chart. That is say a scheduled activities % complete is based on the to-do list.
The only way this chart would be useful is if no one was assigned none dependent task that could be done by anyone. The cases were both of these conditions are true are so few and far between it really makes this chart worthless.
@Brian... Once you have a todo list up and running, it is easy to get metrics out of it. I didnt propose it as it might look a bit too micro-management-ish.
I am able to understand what you meant by "The only way this chart would be useful is if no one was assigned none dependent task that could be done by anyone. The cases were both of these conditions are true are so few and far between it really makes this chart worthless."
Can you explain?
"Chandoo"
What I mean is this. Lets say you have 10 task which are part of one activity/WBS that is in your schedule. One there are very few cases were many people would be assigned to complete this one scheduled activity with no direction being given who should what of the 10 task. It is poor management, and the task 90% of the time would not get done in a timely manner if say 4 people were responsible. Secondly, you are assuming all 10 task are independent of each other. You might need to do task 1 thru 3 before you can do task 4, and to do task 7 you might need to do 4 and 6. Thirdly, the time it would take to compile and then fill out the to-do-list even in limited applications is really not worth it.
I just see almost no applications why a team would need to inform others separate from the schedule that they have completed a task on a to-do list unless anyone of the 4 people could of completed that task.
My point is, there might be a few very limited applications for this type of list but this list would be worthless as a Project Management tool in every other case.
However, change this from a to-do-list to a document change log and it is perfect. Instead of to-do it is the documents name or summary of what changed in the document. The person is who edited the document, and the time stamp is when they checked it in. But I do not know why you would use excel when there is free software you can use commercially that is 10 times better that does document management.
I think using excel to do Project Management over a real Project Management application is a bad idea. Unless you are running a very small, simple project, the time and effort is a lot more to use excel compared to the cost of the Project Management software.
This comes back to my point, I love your site, however, just because you can do something in excel does not mean you should do it. To often the time it takes to use excel is wasted 10 times over from the cost of doing it in an application designed to for the specific application.
@Brian: The todo list mentioned here is meant to keep track of all the tasks for which detailed planning is not necessary but some sort of tracking is needed. These are not be confused with project activities (a la gantt chart).
I like your suggestion about using this as a document tracker. Pretty cool use.
Coming to your point about excel as a real project management tool, well, I have my views, but in a serious project environment, it would surely payoff to have a dedicated project management application.
[...] & tracking a project plan using Gantt Charts Team To Do Lists – Project Tracking Tools Project Status Reporting – Create a Timeline to display milestones Time sheets and Resource [...]
Chandoo,
Wonder how the timestamp column will maintain its previous data. Both Today() and Now() functions will update as and when the next timestamp happens.
[...] Preparing & tracking a project plan using Gantt Charts Part2: Team To Do Lists – Project Tracking Tools Part3: Project Status Reporting – Create a Timeline to display milestones Part4: Time sheets and [...]
I've combined this with the issue tracker since I like the automatic date stamp, but one thing I'm noticing is that I can't replicate the chart that goes along with the issue tracker because the cells that are referenced have the formula that inserts the time stamp instead of a the actual date value. All the dates of the last 30 days display 0 when they should have a value.
Is there a way around this?
I have edited the chart so that my team members can update the percentage completion of the assigned tasks. When the cell is updated, i would like the time stamp to update. How would I manipulate the formula to update whenever the drop-down list is changed?
[...] … ??? To Do List [...]
Excel is great however sometimes you need to get a better idea of what tasks each person on your team is working on at any given time. We've developed a web app that can do just that! Each person has a list of tasks, listed in the order they have to complete them.
HII,
I want to expand the database through excel where i am working on 11 cities as of now and i want to expand it upto 50 cities and hence forth the data related to it will also expand so i want to make it precise where i can get updates also that this work is required to be done at that particular day or date
Thanks for making all of this information available for free. I am currently using excel to track everything for the first time. I later plan to output our information here with a more visual presentation. Wish me luck!
Can some one point me out to some additional direction on the "Who Finished it?" column? Something more 'basic' for a newbie excel guy? lol I got everything else working on this tutorial but that column. I can't seem to recreate it and I know a lot of it is due to lack of knowledge with VB code. I'd like to recreate this column very much 🙁
Dear Chandoo,
Thanks for the team to do list, kindly let me know how to set the column who " finished it " from another work sheet
Hi Chandoo,
Unable to download it - can you please check the link and confirm.
Great inhisgt! That's the answer we've been looking for.
Hi Team,
I know u all are the best programmers in the world!!! that's I am here to rectify my issues. here is my question please ans me as soon as possible before 8-3-2017 its really urgent.
I have a project named the production tracker.
1) I require the user form which shows the names of the Associates which are linked to the different tracks. when the user is selected the particular track related details and dropdowns should appear.
2) I need to track the associate needs how much of the time to complete the particular task. with start stop and pause and resume timer.
3) It should display the daily count of the production and save the data to the another Excel file.
this production tracker should save all the data no matter how many people logs in into it.
Please help me for this it will be very appreciated.
you can directly email me on my mail ID: tusharkch694@gmail.com