Howdy folks. Jeff here. I recently gave a presentation on Excel efficiency to a bunch of analysts, in which – among other things – I’d pointed out that if you ever find yourself having to switch calculation to Manual, there’s probably something wrong with your spreadsheet. Here’s the slide:
This prompted one of the participants to come to me for advise regarding restructuring a spreadsheet with that very problem. This analyst had a file with only 6000 rows of data in it, but the file size was something like 35MB, and after each and every change she had to wait at least a minute for the file to recalculate before she could do something else.
It turns out there were two problems with her files that were easy to resolve.
The Confused range
First, there was a problem with the Used Range – the area within a worksheet that Excel thinks contains all your workings and data. You can find out what this is for each spreadsheet by pushing [Ctrl] + [End], and seeing what cell this takes you to. Hopefully it will take you to the bottom-most, right-most cell that you’ve actually used in the sheet:
But occasionally, you’ll see that it might take you far, far below that cell. Maybe all the way to the very bottom of the grid:
This is bad. Why? Because when Excel saves a file, it includes information about things such as what type of Cell Formatting is used within the used range. If the used range includes millions of cells that aren’t even used, then the information that Excel saves regarding these cells can really blow out the file size. This is exactly what had happened in the case of the spreadsheet concerned. After we reset the used range, the filesize plummeted from 35MB to around 2MB.
Often you can reset the Used Range simply by selecting all the the empty rows under your data, and then deleting them. To do this, select the entire row immediately below your data, then press [Ctrl] + [Down Arrow] to extend the selection right to the bottom of the sheet, then right click and select Delete:
Note that you’ve got to use the Right-Click>DELETE option, NOT the Delete key on the keyboard. Pushing that Delete key does not reset the used range. In fact, this is often why the used range is wrong…it still reflects some data that used to be in the sheet, but that the user subsequently deleted using the keyboard.
When you’ve done this, then push [Ctrl] + [End] again and see where you end up – hopefully at the bottom right corner of your data.
Sometimes this doesn’t fix the problem, and you still find yourself well below your data. In this case, a bit of VBA will usually suffice. I’d suggest putting the below code into your Personal Macro Workbook, for times like this:
Sub ResetUsedRange()
Dim sht As Worksheet
Dim lng As Long
For Each sht In ActiveWorkbook.Worksheets
lng = sht.UsedRange.Rows.Count
Next
End Sub
To see what to do with this code, read What would James Bond have in his Personal Macro Workbook.
Too much SUMIF
The second problem is that each file contained something like 60,000 SUMIF formulas in them. And each one of these formulas referenced two entire columns, rather than just the 2500 rows that actually contained data. It’s really easy to see just how big a problem you might have, simply by doing a Find All for the name of the particular function you’re after:
You can throw 60,000 VLOOKUPS or IF statements or other run-of-the-mill functions at Excel and it won’t even blink. But 60,000 resource-intensive number-crunching functions such as SUMIF, SUMPRODUCT, COUNTIF etc pointed at very large ranges will cause Excel to flinch, if not shut it’s eyes completely for large periods of time.
That’s because these functions are like Ferrari’s…very powerful, but very expensive. One SUMIF is going to travel very fast down the highway. A few hundred SUMIFS on the same stretch are still going to whiz by pretty fast. Tens of thousands of them are just going to crash in to each other:
(The image above comes from this New York Times article detailing a spectacular traffic pileup in Japan in 2011 that left a highway strewn with the smashed wreckage of eight Ferrari’s, a Lamborghini and three Mercedes sports cars. No-one seriously hurt apart from severely injured pride and a marked increase in insurance premiums the following year.)
Often you can use a PivotTable to do the same thing as a whole bunch of functions like SUMIF, COUNTIF, SUMPRODUCT et cetera. PivotTables are natural aggregation and filtering tools. In this case I could use just one PivotTable to replace those 60,000 SUMIFs, and recalculation time dropped from minutes to milliseconds. Now, reporting on this business process is effortless.
One spreadsheet, two morals
I’ve got two morals to share regarding this.
The first is to keep your eyes peeled for signs of trouble in your spreadsheets. Think of FileSize and Recalculation Time as the rev-counter of your car…if it’s getting further and further into the red, then pull over, and check under the hood.
The second – and I can’t underscore this enough – is the importance to organizations of educating all users on how to recognize symptoms of inefficiency. They don’t all have to know how to treat it (although that would be good), but just how to diagnose it. Because if it goes undiagnosed, avoidable inefficiency imposes significant, on-going, and very real opportunity cost. A real dollar amount.
Raising awareness of danger signs is possibly the biggest efficiency gain and risk-reducing opportunity that any training initiative can offer, at the least cost. It’s a game-changer.
Two morals, multiple remedies.
Over at the Daily Dose of Excel blog, I recently posted a mock business case centered around corporate investment in Excel training programme. There’s much more food for thought there, and even more in the comments, so go take a look, and please do leave a comment there with your own thoughts.
While this business case revolves around an internal corporate training programme, another great way of reducing this opportunity cost is through courses such as Chandoo.org’s own Excel School, VBA Classes, and other Chandoo courses.
Not to mention other fantastic courses that you’ll find advertised on the web if you look.
And yet another is though interactions in places like the Chandoo Forum, where you’ll find an army of ninjas with more collective experience than the Borg from Star Trek. The hive mind that is a forum knows no equal.
And of course, you’ll find a wealth of information on this very blog, in articles like I said your spreadsheet is really FAT, not real PHAT!
About the Author.
Jeff Weir – a local of Galactic North up there in Windy Wellington, New Zealand – is more volatile than INDIRECT and more random than RAND. In fact, his state of mind can be pretty much summed up by this:
=NOT(EVEN(PROPER(OR(RIGHT(TODAY())))))
That’s right, pure #VALUE!
Find out more at http:www.heavydutydecisions.co.nz
41 Responses to “Calculate Elapsed Time in Excel [Quick Tips]”
Hi Chandoo,
To calculate time lapses in excel I usually use the DATEDIF function. Even though is undocumented by MS there is a great explanation of its use in Chip Pearson's site :
http://www.cpearson.com/excel/datedif.aspx
Is pretty easy to use and has great flexibility.
See you and keep Excelling!!!
Another great article, I will be linking to it on my blog.
Oliver:
Yes, I think that DATEDIFF do it better.
Great post! This a fantastic tutorial on calculating elapsed time in Excel that could be helpful even to a novice user. Keep up the useful tips!
Also, the Office community on Facebook could really benefit from you knowledge! Check it out at http://www.facebook.com/office
Cheers,
Andy
MSFT Office Outreach Team
hi, Chandoo !!!
for elapsed time , we can use this unique formula either for hours, minutes or seconds : NOW()-A1)
but using respective special number formats
for hours : [h] ==> 46553
for minutes : [m] ==>2793212
for seconds : [s] ==> 167592763
We can also use mean duration for years (orbital period of the Earth around the Sun : i-e tropical year) which is : 365.25 days
and mean duration for month : 365.25/12 days
be Excelent !!!!
@Oliver... Thanks for the pointer to datediff(). I will update the post with information about this as well.
@Glen... thanks for the linklove 🙂
@Andy... Welcome. Thanks for telling us about the office community on FB.
@Modeste ... that is very cool. I will remember these formatting codes for an upcoming article on number formatting codes 🙂
Great tip Chandoo! I use the formula to calculate years elapsed all the time. It can seriously help save a ton of time with calculations. Also, NETWORKDAYS is one that helps and can seriously impress a boss. Keep up the great work here!
No problem! I will definitely be directing people with tough Excel questions to your blog. Keep up the great posts!
Andy
MSFT Office Outreach Team
Hi,
always great posts and a good way to start my day
but regarding the elapsed time calculations: have you never noticed that there is a result difference between using =TODAY()-A1 and using =NETWORKDAYS(A1,TODAY())?
try it for A1= a Monday such as 21sep09 and "today" is e.g. a Thursday; you get 3 or 4 respectively as a result, depending on the formula used; this is because formula =networkdays() always includes both the startdate and the end date and not only the time between these 2.
This is easily corrected/compensated bij always adding a -1 to the =networkdays() formula because the majority of us will count startday as day 0 and then the result will be consistent across the different formulas.
However, you then get into trouble if you calculate the networkdays for a date further in the past and where either the start or end date falls in a weekend.
just thought to point this out as to me these formula's are not interchangeable just like that!
have a great day!
Paul
=DATEDIF([DOJ],TODAY(),"Y") & " Y, " & DATEDIF([DOJ],TODAY(),"YM") & " M, " & DATEDIF([DOJ],TODAY(),"MD") & " D"
This will fix your 30 Days problem
I calculated the time diff between two date+ times by subtracting 2 cells & custom formatted it to "d hh:mm" format.
E.g.
Cell A1 04-Jan-12 6:00 PM
Cell A2 05-Jan-12 4:45 PM
Cell A3 0 22:45 (formula: =A1-A2)
Wat shud i do 2 not display the "zero" values i.e. no. of days in this case is zero hence the cell shud display " 22: 45" and not "0: 22: 45".
@Amol
Try the Custom Format code:
[
<1] hh:mm ; [>=1] d “d” hh:mmHi Chandoo,
If possible to compute the interval of time and date in one column.
In column C I would like to compute the total days and hours . What formula ? Please help
Example.
Column A Column B
2/13/12 3:30 AM 2/14/12 12:00 AM
In referenc to Elapsed time in months
To calculate the elapsed time in months, we can use the formula =(NOW()-A1)/30. This returns the value in 30 day months.
I use to apply formula =ROUND((TODAY()-A1)/30,0). Today, I faced a peculiar situation, A1 has date 01-Mar-2009, and today being 01-Mar-2012, it should be 36 months, but it is showing 37 months!!
Any suggestions to avoid such errors?
Regards,
Prasad DN
All I want to do is add up a series of times and receive a reply that gives me a total. What I used to do was subtrace the end time from the start time and format the result as [hh]:mm but this doesn't seem to work anymore. How has Bill Gates confounded me?
@Pete
I use Excel 2010 and it still works
The times must be entered as times in the format hh:mm:ss or hh:mm without seconds
Adding up times is as simple as =Sum(Range) or =Sum(A2:A10)
then using a Custom Number format as you have mentioned [h]:mm
If this isn't working, 2 ideas
1. Check your times are times and not text
2. Can you share your data or file with us?
My hospital tracks times from patient arrival to various procedures or treatments. When those times cross over midnight, the regular formulas (2nd time minus first time) don’t work because the result is negative and Excel (2007) won’t show a negative number in time format.
I couldn’t find a solution here (chandoo.org) but found one elsewhere that worked and it’s very simple. I would like to share it.
Assuming 1st time in A1 (column for patient arrival time) (11:00 PM), and 2nd time in B1 (column for x-ray given) (12:30 AM)). Should be 1:30 elapsed time.
=B1-A1+(B1<A1) [This comparison is the key to the solution.]
=12:30 AM – 11:00 PM + (12:30 AM < 11:00 PM)
=0.0208 – 0.9583 + (True)
=-0.9375 + (1) [This is the key! If it is false, Excel adds 0. If it’s true, Excel adds 1 and that is what corrects the negative number. Now Excel can interpret the number as a time.]
=0.0625
Converted to hh:mm = 1:30
I wrapped this formula inside an IFERROR one to alert my data entry person if she messed up and applied it to lots of different columns and it has worked wonderfully. No more complaints from the data entry person who just plugs in times from medical charts.
Very interesting solution. Thank you so much for sharing it with all of us.
HI,
I am working on a Xl application..
I want to capture time between two clicks.
Ex, in my application during run somewhere I press OK button and then I click Cancel.. I want to measure time between these two clicks... Is it possible??
Pls help on this...
@shashidhar
The answer is Yes
You will have to add an appropriate VBA event to start and stop a timer.
There are techniques which can time to the millisecond so maybe look those up on the net
WOW!!!!!! I truly love your excel time format program! WHOOOO! I am very interested in how the time formats "update" (manually on a physical keyboard) that "updates" the time into its respective decimal time formats, such as:
YYYY.yyyy, HH.hhh, etc...
How do those formulas or equations work if not in Excel mode? Example: TI calculators, Word, or any other computer language programming? Just wanted to see how it works. E-mail me at Ultra64848689Ti@gmail.com.
Thanks again for an EXCELLENT Excel program into decimal time formats!
Here's an idea: how about creating an APP for iOS and Android? Just wanted to point that out. =-D
Regarding the elapsed time in months:
I made this function to determine the time elapsed since a date using the number of days in each respective month. It's a simple subtraction and I think it works very well:((Year Today-Year A1)*12++(Month Today - Month A1)+(Day Today/Days in Month Today)-Days A1/Days in month A1)
Here's the function:
=((YEAR(TODAY())-YEAR(A1))*12)+(MONTH(TODAY())-MONTH(A1))+(DAY(TODAY())/DAY(DATE(YEAR(TODAY()),MONTH(TODAY())+1,0))-DAY(A1)/DAY(DATE(YEAR(A1),MONTH(A1)+1,0)))
Have a Merry Christmas everyone!!
I need the ability to calculate how much progress we have made between two dates and I want to represent that as a percentage.
I am thinking this would be a combination of today, networkdays & dividing the days elapsed vs the total days. Then it should be as easy as formatting my cell. Any help would be greatly appreciated.
@Christian
Your correct
dates are just numbers and so you can use simple math to derive the percentage
=(Date Now-Start Date)/(End date-Start date)
that will give you a number between 0 and 1
which you can format as a %'age
is there a way out to calculate the productivity for an employee
The day start is at 08:00 and day end is 20:00
The start date / time is recorded and end date / time is recorded
I want to calculate the timelapse taking into consideration the day begin and dayend time.
If the work begins and ends the same day, a simple formula b1-a1 would compute the productivity.
But if the process remains incomplete and is carried over to the next day, then timelines to be computed accordingly
to clarify,
if start time of an activity is 03/15/2015 18:00 hrs and end time is 03/16/2015 11:00 hrs, then the resultant formula should be 5 hrs (ie 18:00 to 20:00 hrs on day1 + 08:00 to 11:00 hrs on day2) ie 2+3
please guide.
Venkatesh, try (b1-a1)-0.5
This will subtract the fixed amount of time between shifts, 12 hours. If the time between shifts varies, then you could reference other cells that contain the variables.
Please help. when I use the networking days formula I get a date (2-may-00) I want actual number of days. I managing projects and I need to know how many days have passed since we received a project to the current date. Please help Thanks
@Aria: Just format the cell as general or number. that will fix the problem.
You rock! I looked at 17 other sites and they all did not work. Yours did. Thanks!
Hi folks ...
calculating age in years , months and days
=text(now()-a1,"yy")&" y " &text(now()-a1,"mm")-1 &" m "&text(now()-a1,"dd") & " d"
Hi, the Elapsed time in days [ =TODAY()-A1 ] works great however, if I do not have a date in A1, it shows 42157. Anyway to get it to display 0 or a Null value?
@Dan
=If(A1="",0,TODAY()-A1)
I get #NAME? and the formula does not work.
Hi Chandoo,
This might be a challenge - I am looking to calculate elapsed time between two columns
Start date Complete date
9/9/2015 7:21 10/2/2015 11:01
I need to take into account the following:
1) The employee works 7:00-3:15 pm each day
2) Std Work hours are 7hrs 45 min each day
3) Need to take into account all holidays in between start and end date
4) Work week is Mon through Friday.
Can you help?
Thanks!
Hi, i have a certain name (wilium) in column A and against this name i have 2 option, 1 Done and 2 Inprogress. i want that i count done again wilium and count inprogress against wilium separately. which formula will work for it??
Hi, i have a certain name (wilium) in column A and against this name i have 2 option, 1 Done and 2 Inprogress in column C. i want that i count done again wilium and count inprogress against wilium separately. which formula will work for it??
Year, month, day results for DoB.
The formulas I have found on the net and the datedif function do not work. This is what I came up with using a Microsoft support paper dated April 1997 with some modifications:
IF(OR(A2>$A$1,ISBLANK(A2)),"",IF(YEAR($A$1)=YEAR(A2),0,IF(MONTH($A$1)>=MONTH(A2),YEAR($A$1)-YEAR(A2),YEAR($A$1)-YEAR(A2)-1))&" years "&MONTH($A$1)-MONTH(A2)+IF(AND(MONTH($A$1)<=MONTH(A2),DAY($A$1)<DAY(A2)),11,IF(AND(MONTH($A$1)=DAY(A2)),12,IF(AND(MONTH($A$1)>MONTH(A2),DAY($A$1)=DAY(A2),ABS(DAY($A$1)-DAY(A2)),DAY(EOMONTH(A2,0))-DAY(A2)+DAY($A$1))&" days")
Check it out...
Hi, Augustin
what about :
calculating age in years , months and days
=YEAR(NOW()-DoB)-1900 & " y " & MONTH(NOW()-DoB)-1 & " m " & DAY(NOW()-DoB) & " d"
Hi Chandoo,
I am looking for help with the elapse time formula. I have a recruitment tracking sheet where we track the number of days the positions are opened, and when they are finally closed.
The opened positions will have a running turnaround time (TAT) formula and I am using this formula:
=NETWORKDAYS (start_date, TODAY (), Holidays2018)
Now, without disrupting the running TAT formula, how do I then get the TAT to stop when we have a final end date? All the information below is row:
- start_date --> Cell A
- TODAY () --> cell B
- end_date --> Cell C
Hope you are able to help. Thanks!
Interesting question. Try this:
Thank you for this helpful article. I was trying for days now to figure it out. Now the only issue I have is that if I do not have a value inputed for =TODAY()-[@[Date Precured]] Date Precured then it shows 44055. How can I get it to leave it blank if there is no data? Thanks again!!!