Today, lets learn how to make a simple timer app using Excel. First some background…,
Recently, I learned how to solve Rubik’s cube from my nephew. As a budding cuber, I wanted to track my progress. Initially I used the stopwatch in my iPhone. But it wont let me track previous times. So I thought, “Well, I can use Excel for this”.
So I made a small timer app using Excel. Its quite minimalistic. It has a single button. I press it and it tracks the start time (date & time stamp). If I press the button again, it records the duration.
This way, I can see my progress over next few weeks and may be plot the trend.
Demo of the Excel VBA timer
Here is a short demo. This is what we will be building.
Tutorial to make a timer in Excel
To make a timer app in Excel, first we need to understand the logic for this. If VBA apps can be defined on a scale of 1 to 10 (1 being easiest to develop and 10 being most complex), our timer app can be classified as 1.5. It is really simple. But nevertheless, it is a good idea to list down various ingredients and basic logic to follow.
So we need,
- A table to store the time stamps & durations
- A button (simple text box will do) to start & stop the timer
Set up the timer worksheet
In a blank worksheet, make space for a 2 column table. Type Time stamp & Duration as column headings and make a table from these (CTRL+T to insert the table)
Note: For the macro to work, you do not need a table. Any 2 column range will do. A table makes our timer app look sexy.
Also, insert a rounded rectangle and format it to look like a button (from Format Ribbon > Shape Styles, select something slick and pretty)
In a blank cell, type the word “Start”. Name this cell as timer.button.label
Now, click on the rounded rectangle button, go to formula bar and type =timer.button.label
💡 Tip: Yes, you can assign names or cell references to shapes. This way, whatever text is in the cell will be shown inside the shape.
Other names to make:
Although we can write VBA code without creating these names, our code will be readable with these names. So here we go:
- Select the header “Timestamp” of the table and name it as time.stamp.start
- Name the table as Durations from Table Design ribbon
- In a blank cell, write the formula =COUNTA(Durations[Timestamp])
- This counts how many timestamps are already inserted.
- Now name this cell as count.of.timestamps
We are done. Lets roll in to VBA.
Writing the VBA code for timer
Open VBE (Visual Basic Editor) and insert a new module in your timer workbook. There write this code.
Sub startStopTimer()
If Range("timer.button.label") = "Start" Then
Range("time.stamp.start").Offset(Range("count.of.timestamps") + 1).Value = Now
Range("timer.button.label") = "Stop"
Else
Range("time.stamp.start").Offset(Range("count.of.timestamps"), 1).Value = Now - Range("time.stamp.start").Offset(Range("count.of.timestamps"))
Range("timer.button.label") = "Start"
End If
End Sub
Assign this macro to the timer button
Right click on timer button and choose “Assign macro”. Select the startStopTimer sub from the list and click ok.
Now go ahead and test it. Assuming you have used same names as per this post, your timer should work.
How this macro works?
When you click on the timer button, you want one of the 2 things to happen.
- You want to start the timer
- You want to stop the timer
What you want to do can be checked with this logical check.
Range("timer.button.label") = "Start"
If this is true, then you want to start the timer.
Else, you want to stop the timer.
If you want to start the timer
Then, we need to go to the last row of the table + 1 and insert current time (now) in that cell.
This is done by,
Range("time.stamp.start").Offset(Range("count.of.timestamps") + 1).Value = Now
Once we do that, we need to change timer button’s text to “Stop”.
This is done by,
Range("timer.button.label") = "Stop"
If you want to stop the timer
Then, we need to go to the last row’s 2nd column of the table and print the difference between latest time (now) and starting time (last row, first column value)
This is done by,
Range("time.stamp.start").Offset(Range("count.of.timestamps"), 1).Value = Now - Range("time.stamp.start").Offset(Range("count.of.timestamps"))
Once we do that, we need to change the button text to “Start” by using this code:
Range("timer.button.label") = "Start"
That’s all. Our VBA code is rather simple.
One last step, formatting the duration
If you look at the duration, it could read something like 0.0042354. This is because duration is displayed as a fraction of day. So 0.0042354 means the duration is 0.42% of a day.
Now, wouldn’t it be better if we can show this in minutes and seconds?
To do that, select the entire table column of durations, press CTRL+1
Then, set formatting as custom and type code as [mm]:ss
And you are done!
Download Simple Timer Excel VBA workbook
Click here to download Simple Timer Excel VBA workbook. Play with it. Use it to track your Sudoku, crossword or knitting times. Or even Rubik’s cube times. See what trends and patterns you can uncover.
Do you use Excel for tracking time?
I know many companies use Excel based trackers to keep track of employee time. I personally use time tracking features of Excel for needs like this all the time.
What about you? Do you use Excel time functions like NOW, TODAY and VBA to track progress? What techniques you apply? Please share using comments.
Like tracking? You will love these
If you track things with Excel, you are going to find below tutorials very useful.
- Tracking issues & risks – Project management
- Tracking to dos – Project Management
- Expense tracker using Excel – 7 templates
- Annual goals tracker
- Bonus: Introduction to VBA – 5 part crash course
Note: Rubik’s cube image by Booyabazooka thru Wikimedia
20 Responses to “Simulating Dice throws – the correct way to do it in excel”
You have an interesting point, but the bell curve theory is nonsense. Certainly it is not what you would want, even if it were true.
Alpha Bravo - Although not a distribution curve in the strict sense, is does reflect the actual results of throwing two physical dice.
And reflects the following . .
There is 1 way of throwing a total of 2
There are 2 ways of throwing a total of 3
There are 3 ways of throwing a total of 4
There are 4 ways of throwing a total of 5
There are 5 ways of throwing a total of 6
There are 6 ways of throwing a total of 7
There are 5 ways of throwing a total of 8
There are 4 ways of throwing a total of 9
There are 3 ways of throwing a total of 10
There are 2 ways of throwing a total of 11
There is 1 way of throwing a total of 12
@alpha bravo ... welcome... 🙂
either your comment or your dice is loaded 😉
I am afraid the distribution shown in the right graph is what you get when you throw a pair of dice in real world. As Karl already explained, it is not random behavior you see when you try to combine 2 random events (individual dice throws), but more of order due to how things work.
@Karl, thanks 🙂
When simulating a coin toss, the ROUND function you used is appropriate. However, your die simulation formula should use INT instead of ROUND:
=INT(RAND()*6)+1
Otherwise, the rounding causes half of each number's predictions to be applied to the next higher number. Also, you'd get a count for 7, which isn't possible in a die.
To illustrate, I set up 1200 trials of each formula in a worksheet and counted the results. The image here shows the table and a histogram of results:
http://peltiertech.com/WordPress/wp-content/img200808/RandonDieTrials.png
@Jon: thanks for pointing this out. You are absolutely right. INT() is what I should I have used instead of ROUND() as it reduces the possibility of having either 1 or 6 by almost half that of having other numbers.
this is such a good thing to learn, helps me a lot in my future simulations.
Btw, the actual graphs I have shown were plotted based on randbetween() and not from rand()*6, so they still hold good.
Updating the post to include your comments as it helps everyone to know this.
By the way, the distribution is not a Gaussian distribution, as Karl points out. However, when you add the simulations of many dice together (i.e., ten throws), the overall results will approximate a Gaussian distribution. If my feeble memory serves me, this is the Central Limit Theorem.
@Jon, that is right, you have to nearly throw infinite number of dice and add their face counts to get a perfect bell curve or Gaussian distribution, but as the central limit theorem suggests, our curve should roughly look like a bell curve... 🙂
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I'm afraid to say that this is a badly stated and ambiguous post, which is likely to cause errors and misunderstanding.
Aside from the initial use of round() instead of int(),.. (you've since corrected), you made several crucial mistakes by not accurately and unambiguously stating the details.
Firstly, you said:
"this little function generates a random fraction between 0 and 1"
Correctly stated this should be:
"this little function generates a random fraction F where 0 <= F < 1".
Secondly, I guess because you were a little fuzzy about the exact range of values returned by rand(), you have then been just as ambiguous in stating:
"I usually write int(rand()*12)+1 if I need a random number between 0 to 12".
(that implies 13 integers, not 12)
Your formula, does not return 13 integers between 0 to 12.
It returns 12 integers between 1 and 12 (inclusive).
-- As rand() returns a random fraction F where 0 <= F < 1, you can obviously can only get integers between 1 and 12 (inclusive) from your formula as stated above, but clearly not zero.
If you had said either:
"I usually write int(rand()*12) if I need a random number between 0 to 11 (inclusive)",
or:
"I usually write int(rand()*12)+1 if I need a random number between 1 to 12 (inclusive)"
then you would have been correct.
Unfortunately, you FAIL! -- repeat 5th grade please!
Your Fifth Grade Maths Teacher
Idk if I'm on the right forum for this or how soon one can reply, but I'm working on a test using Excel and I have a table set up to get all my answers from BUT I need to generate 10,000 answers from this one table. Every time, I try to do this I get 10,000 duplicate answers. I know there has to be some simple command I have left out or not used at all, any help would be extremely helpful! (And I already have the dice figured out lol)
Roll 4Dice with 20Sides (4D20) if the total < 20 add the sum of a rerolled 2D20. What is the average total over 10,000 turns? (Short and sweet)
Like I said when I try to simulate 10,000turns I just get "67" 10,000times -_- help please! 😀
@Justin
This is a good example to use for basic simulation
have a look at the file I have posted at:
https://rapidshare.com/files/1257689536/4_Dice.xlsx
It uses a variable size dice which you set
Has 4 Dice
Throws them 10,000 times
If Total per roll < 20 uses the sum of 2 extra dice Adds up the scores Averages the results You can read more about how it was constructed by reading this post: http://chandoo.org/wp/2010/05/06/data-tables-monte-carlo-simulations-in-excel-a-comprehensive-guide/
Oh derp, i fell for this trap too, thinking i was makeing a good dice roll simulation.. instead of just got an average of everything 😛
Noteably This dice trow simulate page is kinda important, as most roleplay dice games were hard.. i mean, a crit failure or crit hit (rolling double 1's or double 6's) in a a game for example dungeons and dragons, if you dont do the roll each induvidual dice, then theres a higher chance of scoreing a crit hit or a crit failure on attacking..
I've been working on this for awhile. So here's a few issues I've come across and solved.
#1. round() does work, but you add 0.5 as the constant, not 1.
trunc() and int() give you the same distributions as round() when you use the constant 1, so among the three functions they are all equally fair as long as you remember what you're doing when you use one rather than the other. I've proven it with a rough mathematical proof -- I say rough only because I'm not a proper mathematician.
In short, depending on the function (s is the number of sides, and R stands in for RAND() ):
round(f), where f = sR + 0.5
trunc(f), where f = sR + 1
int(f), where f = sR + 1
will all give you the same distribution, meaning that between the three functions they are fair and none favors something more than the others. However...
#2. None of the above gets you around the uneven distribution of possible outcomes of primes not found in the factorization of the base being used (base-10, since we're using decimal; and the prime factorization of 10 is 2 and 5).
With a 10-sided die, where your equation would be
=ROUND(6*RAND()+0.5)
Your distribution of possible values is even across all ten possibilities.
However, if you use the most basic die, a 6-sided die, the distributions favor some rolls over others. Let's assume your random number can only generate down to the thousandths (0.000 ? R ? 0.999). The distribution of possible outcomes of your function are:
1: 167
2: 167
3: 166
4: 167
5: 167
6: 166
So 4 and 6 are always under-represented in the distribution by 1 less than their compatriots. This is true no matter how many decimals you allow, though the distribution gets closer and closer to equal the further towards infinite decimal places you go.
This carries over to all die whose numbers of sides do not factor down to a prime factorization of some exponential values of 2 and 5.
So, then, how can we fix this one, tiny issue in a practical manner that doesn't make our heads hurt or put unnecessary strain on the computer?
Real quick addendum to the above:
Obviously when I put the equation after the example of the 10-sided die, I meant to put a 10*RAND() instead of a 6*RAND(). Oops!
Also, where I have 0.000 ? R ? 0.999, the ?'s are supposed to be less-than-or-equal-to signs but the comments didn't like that. Oh well.
How do you keep adding up the total? I would like to have a cell which keeps adding up the total sum of the two dices, even after a new number is generated in the cells when you refresh or generate new numbers.
So, how do you simulate rolling 12 dice? Do you write int(rand()*6) 12 times?
Is there a simpler way of simulating n dice in Excel?
I've run this code in VBA
Sub generate()
Application.ScreenUpdating = False
Application.Calculation = False
Dim app, i As Long
Set app = Application.WorksheetFunction
For i = 3 To 10002
Cells(i, 3).Value = i - 2
Cells(i, 4).Value = app.RandBetween(2, 12)
Cells(i, 5).Value = app.RandBetween(1, 6) + app.RandBetween(1, 6)
Next
Application.ScreenUpdating = True
Application.Calculation = True
End Sub
But I get the same distribution for both columns 4 and 5
Why ?
@Mohammed
I would expect to get the same distribution as you have effectively used the same function