Last week I have reviewed Google’s flu trends chart and told you why it is an awesome chart. This week, I am going to show you how such a chart can be constructed in Excel.
First let me show you what I am able to do in Excel:

(compare this with actual chart on Google)
How I made the flu-trends chart in excel?
- Data, Data, Data: Data plays an important role in complex charts like these. The source data is thankfully available for download from Google. Flu incidence data is available by week (Sunday to Saturday) for every week since 28th Sep, 2003. For each week the data if given for all regions in various columns. But I was not able to use the data “as-is” to construct this chart. I had to massage and rearrange it a bit.
- The main issues is how flu season is classified (it starts on July and ends in June) and how the data is (we got weekly flu incident data, starting from Sunday to Saturday). The main issue here is each year, the weeks start on different dates. For eg. first Sunday in 2010 was on 3rd Jan where as in 2009 it was on 4th Jan. I tried using WEEKNUM() formula (examples), but it didn’t work well with the flu season (Jul to Jun). So I did some basic date math and ended up mapping weeks uniformly across years.
- The next issue is taking one big table of data with dates in rows and regions in columns and transform it to weeks in rows, years and columns and actual flu data for the selected region in the cells.
- Then I set up 2 cells, one where user would specify “region” and other where a comparison “year” can be selected. I have used data validation to control the valid inputs.
- I used the MATCH, INDEX formulas to fetch corresponding weekly values for all years for selected region. Thanks to MATCH, INDEX and HLOOKUP formulas, this is not such a big task either. And if the optional comparison year is specified, we repeat that years values in another column. Otherwise that column is NA().
- Using these columns, I made a line chart. Then I cleaned up the chart and formatted the 2009-2010 series in thick blue and rest all in thin light blues. The optional comparison series was colored in red (for contrast). [related: line chart examples]
- The only remaining piece is to show the heat map of flu intensities below the chart. For this I have used the very useful 3 color scale conditional formatting setting in Excel 2007. (of course, I had to setup some extra calculations so that the intensities are normalized across the region / years and change when user selects a new region, but you already guessed it.)

- I choose to drop the colorful legend as it adds little value.
- The rest is some formatting and presentation.
What I learned from this experience?
- When I looked at Google’s chart, I doubted if it can be created in Excel. But I was wrong. It can be done in excel, and it takes no more than 2 hours.
- Data and structure of it play extremely important role in any visualization.We should understand the data and know how to arrange / transform / massage it, to make better charts.
- Date formulas are a flu in the nose.
- Excel 2007 conditional formatting is just awesome. [more examples]
- INDEX, MATCH, LOOKUP formulas are very powerful. I *respect* them. [here is a tutorial]
Download flu trends chart and play with it
Download the file (Excel 2007 only). The file is locked, but there is no password. Play with it and tell me if you like it.
Do you like this chart?
Have you done something similar in Excel? What was your experience like? Do you like this chart? How would you improve / change it?
More visualizations using Excel:
Olympic Medals by Country | Survey Results Dashboard | Test Cricket Statistics | Dynamic Charts
PS: After a looong time this post had many “I”s
PPS: Have a good weekend.














15 Responses to “Christmas Gift List – Set your budget and track gifts using Excel”
[...] Christmas Gift List – Set your budget and track gifts using Excel … [...]
I'm confused: if you spend $10, and your budget is $40, shouldn't the amount in the "Within Budget?" column stay black, since you didn't go over budget?
In other words, since we overspent on the electronic photo frame, shouldn't the $8 cell turn red?
@JP.. maybe Steven is encouraging consumerism... ?
I havent realized it earlier, but now I see it. If you unprotect the sheet, you can change the formula in Column I to =IF(G13=0;" ";F13-G13) from =IF(G13=0;" ";G13-F13), that should correct the behavior.
Thanks Chandoo. I thought of making a shopping list spreadsheet for Christmas, but this is neat so I think I'll use this instead.
Chandoo & Steven thanks for this spreadsheet. But for the sake of a person who has been staring at this megaformula in vain for the last 40 mins and not afraid to ask, would it be possible for you to walk us through the logic used here?
=SUM(SUMPRODUCT(SUBTOTAL(3,OFFSET($K$13:$K$62,ROW($K$13:$K$62)-MIN(ROW($K$13:$K$62)),0,1)),--($K$13:$K$62="-"))+SUMPRODUCT(SUBTOTAL(3,OFFSET($K$13:$K$62,ROW($K$13:$K$62)-MIN(ROW($K$13:$K$62)),0,1)),--($K$13:$K$62="0")))&" / "&SUBTOTAL(2,$G$13:$G$62)
Thanks Chandoo.. This is one of the best budget spreadsheets I've ever seen.. The Arrays are out of this world!! And it's FREE!!
Chandoo, can you tell us more about Steven? Does he have his own site?
JP, I think Chandoo changed it when he changed the currency formatting from £ to $, a negative figure is a good thing in this case. But don't change the formulas, the overbudget and under budget won't work properly if you do. Also Chandoo I think you've accidentally broke the conditional formatting for the alternating row colouring the formula is different to the version I sent you. As for the megaformula chrisham, it gave me a headache trying to get it all working, so I will let Chandoo talk you through it.
Hi,
In cells I6 and I7, I understand that subtotal together with offset function returns an array of ones after which, the sumproduct function gives the desired result.
But I’m not able to figure out the reason for using an array in I8 to return the most expensive gift.
Can’t the formula be just
“=VLOOKUP(SUBTOTAL(4,$G$13:$G$62),$G$13:$J$62,4,0)”
Savithri, Cell I8 needs the array, if the formula was “=VLOOKUP(SUBTOTAL(4,$G$13:$G$62),$G$13:$J$62,4,0)” it would find the highest price from the filtered range (i.e. highest actual in filtered range is $50) BUT then return the first person with that actual, not looking in just the filtered range (so first person on the list with a $50 actual.)
To see what I mean, change the formula, then change all the actuals to $50 then filter for baby, it lists the first name on the list.
But a good question 🙂
Thank you. I now realise that the array is used to get the ‘filtered range’ instead of the entire range, as table array for look up value.
[...] Download This Template [...]
this looks like an awesome excel sheet!! is there anyway i can get it emailed to me unprotected? for some reason, i am unable to download it 🙁 help!!
Hi I also can not download to a mac as the sheet is protected any help would be great
[...] to send her a pricey present. Rather, send a card with a picture of your child. Here’s a cool Excel sheet that will help you estimate your budget per person and let you track [...]
[...] husband and I pour/poor over the Christmas spreadsheet (yes, I do know how dorky that sounds, but we’re not the only ones!), figuring out who should give what to whom. We live at a distance from most of our family, so it [...]