Often when we are making spreadsheets for forecasting or planning we would like to keep the starting month dynamic so that rest of the months in the plan can automatically rolled. Don’t understand? See this example:
This type of setup is quite useful as it lets us change the starting month very easily. We can use such a set up in, for eg. Gantt Charts to change the project start dates with ease. Today we are going to learn how to set up automatic rolling months in Excel.
To set up such dynamic rolling months in Excel, just follow these simple steps:
1: Create a list of all the months
Enter the month names in a bunch of cells (Tip: Just enter the first month name and then click at the bottom right corner of that cell and drag to get all the other month names). Let us call this range as B5:B16. If you prefer, name this range as “lstMonths“.
2: Set up data validation drop down list on the first cell for automatic rolling
Now, let us assume we will use cells A1:A12 for automatic rolling months. Select A1 and set up data validation list on it (so that users can only enter a valid month in that cell) and use “List” type as validation. See below:
3: Now write formulas so that we fetch consecutive months based on first month
(Thanks to comments from Jeff, Hui, Vipul and others. I found a simpler and easier way to write the formula)
We will simply use Excel’s date formulas so that we can fetch consecutive rolling months based on the first selection.
Assuming the date is selected in cell A1,
In A2, write the formula:
=DATE(2010,MATCH($A$1,lstMonths,0)+COLUMNS($A$2:A2),1)
What is above formula doing?
- It is using the DATE Formula to create a next months first date.
- The part MATCH($A$1,lstMonths,0) is used to fetch the position of selected month in the range lstMonths
- The part COLUMNS($A$2:A2) is used to generate the sequential numbers in excel.
- Make sure you have formatted the cells A2:A12 as “date” with code “mmm” to show 3 letter month codes.
- Rest all you can figure out easily 🙂
A more complex solution
in-case you got some other types of values instead of months:
To make it a bit simple, I will use a helper cell where we can identify the position of selected month in the list of months, like this:
I have assumed that Jan is 0, Feb is 1 … Dec is 11. Also, assume, the helper cell is in $B$4.
Now, If the selected month is “5”, then the other months will be 6,7,8,9,10,11,0,1,2,3,4.
The interesting part here is the sudden jump from 11 to 0 as highlighted above.
To get this type of output we must use an excel formula called as MOD.
What is Excel MOD Formula?
MOD formula takes 2 numbers tells us the remainder when first number is divided by second number. [Excel MOD formula, Introduction, Syntax & Examples]
So how to use MOD formula to setup rolling months?
Very simple. We just take the value in $B$4 (position of the first month in the list) and then add +1 to it and then find out the MOD of it when divided by 12. We now use this number to fetch the corresponding month from lstMonths.
We use +2 for second month…. +11 for the last month.
We can simplify the +1, +2..+11 part by using COLUMNS formula to generate the sequential numbers for us.
The formula looks like this:
=INDEX(lstMonths,MOD($B$4+COLUMNS($A$2:A2),12)+1)
- The Mod portion of this formula tells the position of the second, third, fourth, … eleventh month based on the first month.
- We have to add +1 to output from MOD because we are using 0,1,2,3 positioning the month in B4, where as INDEX use 1,2,3,4 positioning.
- INDEX formula then fetches the corresponding month from
lstMonths(orB5:B16)
That is all.
Download the example workbook and learn on your own
I have prepared a short example workbook where this technique is demonstrated. Feel free to download it and play with it to learn more.
Where would you use such a rolling month setup?
I have once used the rolling month set up in a forecasting spreadsheet (where we made cash flow projections for a startup we were planning to acquire). I am also planning to upgrade my gantt chart templates include rolling month setup.
What about you? Where would you use automatic rolling months?
40 Responses to “Looking up when the data won’t co-operate (case study)”
Nice Trick.. Clever use of cell references
Here is a formula I tried to create:
=SUMPRODUCT(((NOT(ISERROR(SEARCH(L5,B4:H14))))*1),(B5:H15))
It takes care of Caveat #1 (can handle text), but Caveat #2 remains.
In situations like this, I will often use VBA to restructure the data (2 columns: dates and values) on to a new worksheet. I can then use this 'clean' source for data analysis (formula or pivot table).
=SUMPRODUCT(((NOT(ISERROR(SEARCH(L5,B4:H14))))*1),(B5:H15)) and complex formulae in general are all very well but when you come back to them in a few weeks / months time, it is not at all easy to see what they do and what the limitations are.
Hi Chandoo,
I had used this type of cell ref. various times while calculating average.
But for the situation here try below formula . Note this is an array formula and must be confirmed with Ctrl+Shift+Enter.
=SMALL(IF(MMULT((L5=B4:H14)*IF(ISNUMBER(B5:H15),B5:H15),{1;1;1;1;1;1;1}),MMULT((L5=B4:H14)*IF(ISNUMBER(B5:H15),B5:H15),{1;1;1;1;1;1;1})),1)
Regards,
Hi, I think Using SEARCH in here will create a problem say there is a text like SUN and another text SUNLIGHT both result will be added by SUMPRODUCT.
Regards,
Array option.
=SUM(IF(MOD(ROW(B4:B14),2)=MOD(ROW(B4),2),IF(B4:H14=L5,B5:H15)))
Regards
@Elias,
Nice approach.
Although not requested - the formula I suggested closes all possibilities.
Criteria: _____ Value to retrieve:
Date__________ Numeric
Date__________Textual
Textual________Numeric
Textual________Textual
While your formula copes with only the 3 first combinations.
Michael (Micky) Avidan
“Microsoft® Answer” – Wiki author & Forums Moderator
“Microsoft®” MVP – Excel (2009-2015)
ISRAEL
@Michael,
Sorry but I don’t understand your point. I believe the challenge was to return the summary of a given date. What is your really volatile formula doing that mine is not?
Regards
@Elias,
I didn't say that the challenge differs from what you just mentioned/aimed to nor that your formula doesn't provide the requested result.
Please read my previous comment again and focus on the last combination (TEXT / TEXT).
I, myself, always try to provide a global Formula that is capable to handle all sorts of data.
Michael (Micky) Avidan
“Microsoft® Answer” – Wiki author & Forums Moderator
“Microsoft®” MVP – Excel (2009-2015)
ISRAEL
@Michael,
I see your point, but you are missing the below points if you are trying to cover all sorts of data.
What happened if the lookup value does not exist?
Do you want the first, second, summary, concatenation of the values if the look value is repeated?
See they are too many possibilities to be cover with just one formula.
Regards
1) The range: B4:H15 was named: RNG.
2) The following Array Formula was "retrieved from my sleeve" and I hope it can be shorten.
3) The formula seems to take care of BOTH(!) caveats.
-------------------------------------------------------------------------------
=OFFSET(INDIRECT(ADDRESS(SMALL(IF(RNG=L5,ROW(RNG),""),1),MOD(SMALL(IF(RNG=L5,(ROW(RNG))+COLUMN(RNG)/10),1),1)*10)),1,)
-------------------------------------------------------------------------------
Michael (Micky) Avidan
“Microsoft® Answer” – Wiki author & Forums Moderator
“Microsoft®” MVP – Excel (2009-2015)
ISRAEL
@Michael,
Check what happened with your result if you type 41927 in D5.
Regards
Correct. Didn't predict that.
Will find time to work something out.
Michael (Micky) Avidan
“Microsoft® Answer” – Wiki author & Forums Moderator
“Microsoft®” MVP – Excel (2009-2015)
ISRAEL
@Elias,
Let's hope the following Array Formula "closes all open doors".
Again - it has nothing to do with your formula which works fine as long as the 3 first mentioned combinations are concerned.
-------------------------------------------------------------------------------
=INDEX(RNG,LARGE(IF(RNG=L5,MOD(ROW(RNG)-1,2)*(ROW(RNG)),""),1)-2,(MOD(SMALL(IF(RNG=L5,(ROW(RNG))+COLUMN(RNG)/10),1),1)*10)-1)
-------------------------------------------------------------------------------
Michael (Micky) Avidan
“Microsoft® Answer” – Wiki author & Forums Moderator
“Microsoft®” MVP – Excel (2009-2015)
ISRAEL
Ok, if you insist. The following will cover all the scenarios you listed. However, I’ll never recommend/use such of formula.
Defined names:
rDat = $B$4:$H$15
rRow =ROW(rDat)-MIN(ROW(rDat))+1
rCol =COLUMN(rDat)-MIN(COLUMN(rDat))+1
rInc =MOD(rRow,2)=MOD(MIN(rRow),2)
L6=INDEX(rDat,MAX(IF(rInc,IF(rDat=L5,rRow)))+1,MAX(IF(rInc,IF(rDat=L5,rCol))))
Array Enter
Regards
@Michael,
unfortunately, your array formula still seems to return wrong results (eg 3-Nov).
If data are organized like in the example, ie. looks like a calendar, the INDEX formula seems quite simple:
=INDEX($B$4:$H$15,ROUNDDOWN((L5-B4)/7,0)*2+2,MOD((L5-B4),7)+1)
Yours is effectively the same as what I just came up with, and I believe this is the optimal answer to this particular problem.
My solution, before I saw yours:
=OFFSET(B5,QUOTIENT(L5-B4,7)*2,MOD(L5-B4,7))
OFFSET will work for an arbitrary list size, but INDEX might be easier to read.
QUOTIENT does the round and division in a single step.
If there's an improvement over Elias's solution then I for one can't see it.
Perhaps a non-CSE version which would also mean that only two references (B4:H14 and B5:H15), as opposed to three (B4, B4:B14 and and B5:H15), would require manually amending should the data range change, i.e.:
=SUMPRODUCT((ISEVEN(ROW(B4:H14)-MIN(ROW(B4:H14)))*(B4:H14=L5)*B5:H15))
I suppose we could make it a single, uniform range reference:
=SUMPRODUCT((ISEVEN(ROW(B4:H14)-MIN(ROW(B4:H14)))*(B4:H14=L5)*OFFSET(B4:H14,1,,,)))
which might be more appropriate should we e.g. wish to use a Defined Name for our range, i.e.:
=SUMPRODUCT((ISEVEN(ROW(Rng)-MIN(ROW(Rng)))*(Rng=L5)*OFFSET(Rng,1,,,)))
though whether that compensates for the extra, volatile function call is something to be debated.
Regards
I have tried something and then my Excel workbooks got shut down. Maybe that was too much?
Anyway here is what I've tried:
=SUMPRODUCT(INDEX(B5:H15;IF(ISEVEN(ROW(B5:H15));ROW(B5:B15)-ROW(B5)+1);{1\2\3\4\5\6\7}))
Guess that was wrong? Would this approach work anyway?
Looking forward to learn something from you Excel Experts.
Sorry, I haven't took notice of XOR LX's answer. I guess that's kind of what I was looking for.
@Michael Avidan
As it stands that is not a very rigorous construction.
You say "I, myself, always try to provide a global Formula that is capable to handle all sorts of data", which is a wonderful philosophy, but isn't it at least as important that we ensure that our formulas are independent of the row and column references of the data range in question, so that, should that range change, we do not have to re-work our solution?
What happens with your formula, for example, if RNG is instead re-located one row down, from B4:H15 to B5:H16?
When a formula is reliant upon the addition/subtraction of certain constants within the formula, which themselves are necessarily dependent upon the specific rows/columns in which the data lies at any given time (e.g. the -1 in MOD(ROW(RNG)-1,2)), then that formula is not a very flexible one.
Hence the reason for my choice of a slightly longer construction:
ROW(B4:H14)-MIN(ROW(B4:H14))
which ensures that this part of the calculation is not dependent upon the precise location of the data range within the worksheet, and so will give correct answers even if that range is re-located.
Regards
{=OFFSET(B4,MAX((B4:H15=L5)*ISODD(ROW(1:12))*ROW(1:12)),MAX((B4:H15=L5)*ISODD(ROW(1:12))*COLUMN(A:G))-1)}
Non-array formula:
=INDEX(B4:H15,SUMPRODUCT((B4:H15=L5)*(ROW(B4:H15)-ROW(B4)+1)*ISODD(ROW(B4:H15)-ROW(B4)+1))+1,SUMPRODUCT((B4:H15=L5)*(COLUMN(B4:H15)-COLUMN(B4)+1)*ISODD(ROW(B4:H15)-ROW(B4)+1)))
Using one range (B4:H15), one reference (B4), one lookup value (L5) and no INDIRECT or OFFSET.
My trial with defined names:
DateRange
=$B$4:$H$4,$B$6:$H$6,$B$8:$H$8,$B$10:$H$10,$B$12:$H$12,$B$14:$H$14
Position
=RANK('lookup problem'!$L$5,DateRange,1)
L6
=OFFSET(B4,ROUNDUP(Position/7,0)*2- 1,IF(MOD(Position,7)=0,6,MOD(Position,7)-1))
I'd probably just run with something like:
=SUMPRODUCT((B4:H14=L5)*(MOD(ROW(B4:H14),2)=MOD(ROW(B4),2))*B5:H15)
...which is basically the same as Elias' but without the IFs
The opposite of elegant but it works...
=INDEX(B4:H15,IFERROR(MATCH(L5,B4:B14,0),0)+IFERROR(MATCH(L5,C4:C14,0),0)+IFERROR(MATCH(L5,D4:D14,0),0)+IFERROR(MATCH(L5,E4:E14,0),0)+IFERROR(MATCH(L5,F4:F14,0),0)+IFERROR(MATCH(L5,G4:G14,0),0)+IFERROR(MATCH(L5,H4:H14,0),0)+1,IFERROR(MATCH(L5,B4:H4,0),0)+IFERROR(MATCH(L5,B6:H6,0),0)+IFERROR(MATCH(L5,B8:H8,0),0)+IFERROR(MATCH(L5,B10:H10,0),0)+IFERROR(MATCH(L5,B12:H12,0),0)+IFERROR(MATCH(L5,B14:H14,0),0))
=INDEX(B4:H15,
IFERROR(MATCH(L5,B4:B14,0),0)+
IFERROR(MATCH(L5,C4:C14,0),0)+
IFERROR(MATCH(L5,D4:D14,0),0)+
IFERROR(MATCH(L5,E4:E14,0),0)+
IFERROR(MATCH(L5,F4:F14,0),0)+
IFERROR(MATCH(L5,G4:G14,0),0)+
IFERROR(MATCH(L5,H4:H14,0),0)+1,
IFERROR(MATCH(L5,B4:H4,0),0)+
IFERROR(MATCH(L5,B6:H6,0),0)+
IFERROR(MATCH(L5,B8:H8,0),0)+
IFERROR(MATCH(L5,B10:H10,0),0)+
IFERROR(MATCH(L5,B12:H12,0),0)+
IFERROR(MATCH(L5,B14:H14,0),0))
Named Range
rownum = SUMPRODUCT(('lookup problem'!$B$4:$H$14='lookup problem'!$L$5)*ROW('lookup problem'!$B$4:$H$14)*ISEVEN(ROW('lookup problem'!$B$4:$H$14)))
Formula
=OFFSET($A$1,rownum,MATCH(L5,INDIRECT("$B"&rownum&":$H"&rownum),0))
How about SUM(IF(B4:H14=L5,B5:H15)) with array..it should work
Sorry, Chandoo, you can't find stuff this way in every possible scenario.
What if 2014-10-01 sales would equal 41.927 ? Which is serial number for 2014-10-15 ? SUMIF would fail to retrive correct answer. And your example data suggest that such number is possible in your table.
It's better not to search through dates and numbers at the same time.
If I'd solve a problem like this, it'd reformat table first so I get one column with dates and the other with numbers.
In this case, formula to form date column would be:
=INDIRECT(ADDRESS((INT((ROW()-4)/COUNT($B$4:$H$4))+1)*2+2;MOD(ROW()-4;COUNT($B$4:$H$4))+2;4;1))
and numbers would be the same formula with sight adjustment (+3 instead of +2 at the end of first argument):
=INDIRECT(ADDRESS((INT((ROW()-4)/COUNT($B$4:$H$4))+1)*2+3;MOD(ROW()-4;COUNT($B$4:$H$4))+2;4;1))
And now you got two columns that you can safely use for searching!
Oops, sorry, you actually mentioned that it doesn't work if number=date! I missed that part 🙁
={OFFSET(A1,SUM((B4:H14=L5)*ROW((B4:H14))),SUM((B4:H14=L5)*COLUMN((B4:H14)))-1)}
Works for all data... the solution I got for indirect looks little lengthy
I want to count last 20 records of a person, whose marks is greater than 2 and grade "manager". ....
Assume A1 has got names (James, John...etc...)
A2 "Manager"
A3 "2"
Someone please reply
I want to count last 20 records of a person, whose marks is greater than "2" and grade "Manager"
Assume A1 "geroge" A2 "Michael" A3 "George" etc...name can found anywhere in the rows
B1 "Manager" B2" clerk"
C1 "2" C2, "4"
please reply
Simplest I can come up with. No limitations for either 1 or 2. This does assume dates are an ordered list with 7 per row, and 2 rows per set. Assuming this is always true this will work for an arbitrary long list of dates.
=OFFSET(B5,QUOTIENT($L$5-$B$4,7)*2,MOD($L$5-$B$4,7))
@Marc,
Nice approach - however, as there are no "Negative Dates" - try:
=OFFSET(B5,INT(L5-B4)/7)*2,MOD(L5-B4,7))
——————————————————————————-
Michael (Micky) Avidan
“Microsoft® Answer” – Wiki author & Forums Moderator
“Microsoft®” MVP – Excel (2009-2015)
ISRAEL
=OFFSET(B4,ROUNDUP((L5-41911+1)/7,0)*2-1,MOD(L5-41911,7))
B4 has been used as reference cell for OFFSET().
FOR ROWS:
ROUNDUP(....,0) gives the integer value of a division. In case of presence of a remainder, ROUNDUP will add 1 to the Quotient.
As opposed to ROUNDUP(), the INT() or QUOTIENT() functions eliminate the remainder.
41911 = 01-Sept-2014, the first date in the data.
*2 has been used because there are 2 columns per set of data.
/7 has been used because there are 7 columns per set of data.
For columns
MOD(L5-41911,7))
Vijaykumar Shetye,
Panaji, Goa, India
This is how i did it
{=INDEX(B4:H15, MAX((L5=B4:H15)*ROW(B4:H15))-2, MAX((L5=B4:H15)*COLUMN(B4:H15))-1 )}
Here's my solution:
=INDEX(B4:H15,MATCH(1,MMULT(--(B4:H15=L5),TRANSPOSE(COLUMN(B4:H15)^0)),0)+1,MATCH(1,MMULT(TRANSPOSE(--(B4:H15=L5)),ROW(B4:H15)^0),0))
Sorry, forgot to mention Ctrl Shift Enter is needed.