In mid May, Anup47 asked a question in the Chandoo.org forums about the use of a VBA macro to run a number of iterations of a variable against two sets of X values, you can see the post here. It turns out that the number of iterations was 500 columns of data with each column having 27 values.
On examination of the problem, it was going to be a straight forward matter of setting up a statistical function Linest and then using the Data Table command to run each set of data through the function.
The Linest will take the input data and return the statistics that Anup wanted.
The Data Table function will feed in the source data and tabulate the Input and Output data.
This Post follows through a worked example which you can follow along, download the Sample file to suit Sample File 97/2003 or Sample File 2007/10 version. The Sample File contains a worked example of the completed model as well as a Practice Page of the original data. Download the Excel 95/2003 or 2007/10 version above.
Please note that the sample file only contains 14 sets of data as opposed to the 500 Anup47 wanted to process.
Setup
There are a few things that needed setting up before the work starts.
- Headers
- Linest Area
- Link Area
- Data Table Area
Once these areas are setup we simply use the Excel Data Table function.
Once the Data Table function has run, the results can be processed or analysed as required.
Headers
The original data was just that, a tabulation of raw data. The two X sets of Data were in Columns 1 & 2. Each Column from D onwards has a set of Y data that was to be processed.
The first thing that was required was some Headers for the Input Data.
This isn’t strictly required but it is good practice and makes it easier to tabulate and analyse results later.
Insert a Row above the first line
Put X1, X2 in A1, B1 and Y1 in D1 and then drag the lower right Black Handle across top to the right and Excel will autofill the remaining cells.
Linest Area
To get the statistics which Anup wanted we will use the Excel Linest function.
Linest is a Statistical Function that takes a set of data and compares it, in this case to two sets of X Values and produces a set of statistical measure relevant to the correlation between the data sets.
This post isn’t going to explain the intricacies of Linest and I refer you to the Links section at the end where you can read more about the Linest function at your leisure.
For our purposes we need to know that Linest is an Array Formula and requires a 5 Row x 5 Column area to be entered into. For now we will just Array Enter the function =Linest($D$2:$D$28,A2:B28,True, True) into B32:F36.
To do that select the range B32:F36, Press F2 and type/paste the equation in, then Array Enter with Ctrl Shift Enter.
Link Area
To Link the Linest equation to a Data Table we need a link cell, which we will put just above the Linest area.
For now just enter a 1 in it.
We can now go back to the Linest area and link the Linest equation to our link area using the equation, =LINEST(OFFSET($C$2:$C$28,,$B$30),A2:B28,TRUE, TRUE)
To do that select the range B32:F36, Press F2 and type/paste the equation in, then Array Enter with Ctrl Shift Enter.
What this does is allow the Linest formula to access different columns Y1 to Y500 depending on the value of the Link cell B30 which is now 1.
Data Table Area
To setup a Data Table area we need a column of Inputs which will be the Run Numbers and the Row Inputs will be links to the Input and Output Cells.
In a range J33:J46 put the values 1 to 14. These will be the Run Numbers. ie Run No 1, Run No 2 etc (Green in the example below).
Across the top of the Data Table area we can put a number of links and associated labels (Yellow and Blue)
In this case there are 4 Output links =B31, =C31, =B34 and =B33 and their associated labels above them, as well as 2 Input equations and there Labels. The Input equations are simple Offset function that retrieves a value from Rows 1 or 2 based on the value of the Link Cell B30.
These are technically not required but make data analysis and identification of individual results later on a lot simpler.
Run Data Table
We can now run the data Table by selecting the Data Table area: J32:P46
Noting that we will be using a Column Input cell and that it will link to $B$30, the Link cell for the Linest command.
What this does is takes the first value from the Column J32:J46 and puts it into B30, then the Linest command will be calculated and the results put into the Data Table area along with the Inputs.
This is repeated for each cell in J32:J46 automatically.
The final Data Table is now populated as below:
You can see by extending the Data Table input column from 14 to 500 that the full 500 columns of Input Data could easily be processed.
Results
You now have a set-off data that can be analyzed using normal statistics, Min, Max, Std Deviation etc, or can be fed into a Pivot Table/Chart for analysis etc.
References
Linest References
http://chandoo.org/wp/2011/01/26/trendlines-and-forecasting-in-excel-part-2/
http://newtonexcelbach.wordpress.com/2011/01/19/using-linest-for-non-linear-curve-fitting/
Data Table References
http://chandoo.org/wp/2010/05/06/data-tables-monte-carlo-simulations-in-excel-a-comprehensive-guide/
How can the Data Table command help you become a data processing super hero?
How can the Data Table command help you become a data processing super hero?
Let us know in the comments below:
20 Responses to “Mortgage Calculator with Extra Payments – Excel Download”
Kia ora Chandoo, thanks for this wonderful template brother. How can I modify this/ or do you have a similar template for a fortnightly
payment? Thank you
Morena Rayd. You can adjust the multiplier / divider to 26 (I think it was set to 12) to see fortnightly details. Watch the companion video to understand the steps / logic.
It is very simple and easy to use. Is user interface is attractive. It is very helpful and beneficial for calculations.
This is great, thanks a lot!
I think there is an error in the "You save X $ in interest". If i dont put any extra payment, it still says that I will save 19k in interest rate.
I too realized this problem. I will post an update once I fix the error.
Updated on 11-Sep: I fixed the problem with "interest saved" calculation. Turns out there was an internal bug in cumipmt function in Excel that reports incorrect values. Something new!
Please use the link above to re-download the correct file.
Hi Chandoo, do you have a template that will make changes to figures going forward if the interest rate changes part way through the loan? Thank you for your help.
I wanted calculator which can consider floating interest rate, can you please advise how to get that?
I love your tutorial. If I am making weekly acelerated mortgage payments, how to I account for that in the Eff term?
Thank yo so much,
Christine
Hi Chandoo. I want an excel template where I can have my favourite stocks listed for which the prices changes on a dynamic basis every day as per the market. I mean a sheet which is linked to NSE for price changes and other changes like daily low, Daily high, Yesterday closing, last 10 day range, 52 week high, 52 week low, one month high, one month low, one week high and one week low etc
The excel is awesome but I am getting #NAME? error with the field 'Old Interest Paid' and subsequently Original Interest and Money saved. Can you tell me how to fix that. I am trying to check if I should complete my loan by the extra payments or instead invest the same amount elsewhere
#NAME error could mean your Excel doesn't have one of the functions I am using. Can you tell me what version you are using? If I am not mistaken, this file requires Excel 365.
Hi Chandoo, I am also getting the same error. I am using Office 2019. Would you be able to recommend a fix for this?
Regards,
How do you change the dollar to rupees for whole sheet to match indian currency
You can select the values and apply rupee formatting from cell formatting options.
Hey Chandoo,
Thank you for making the excel spreadsheet! It is great, but there another, little known money saving action that you can take to DRAMATICALLY reduce your total interest owed on your mortgage allowing you to pay it off 40% to 60% faster. I am going to share with you for free. It's called recasting your mortgage, which is a form of re-amortizing the interest that you owe on your loan by paying the the bank an early payment of $10,000 or more. The bank will modify your loan to cancel the original interest that you owe, and recalculate the total interest based on the new lower loan loan amount for the remaining term of the loan, instead of the original loan amount. This pays off the most expensive section of interest on your loan which is the next owed interest, instead of cancelling the interest at the end of your loan. Your charts show the interest being canceled on the last payments, however the interest can be canceled on your next upcoming portion of the loan, but keeps the ending date the same. However, the result of recasting the loan is you, pay the loan off 2 or 3 times faster, by paying off the portion of the loan with the highest interest cost. I am wondering if you can build a excel spreadsheet that shows this for me? I will pay you for making it. I am a mortgage loan officer and would like to use it to help my clients see the impact of paying off their loans this way. Thank you for considering this!
HI Chandoo.
Excellent sheet i watched your video and tried to edit sheet to suit my current mortgage however i cant get it to work. I am trying to set it to weekly payments.
I edited the monthly payments to =PMT(E7/52,E6*52,E5)
eff.term =ROUND(NPER($E$7/52,$E$10,$D13),0)
principal term to =PPMT($E$7/52,1,E13,D13)
cb w/o to =IF(C13=1,$E$5,J12)+PPMT($E$7/52,C13,$E$6*52,$E$5)
and interest paid to =IPMT($E$7/52,1,E13,D13) but i cant edit the arrays to increase the range to 1560 from 360, so i just added the numbers in and that worked for the array on the left but the old interest paid array im stuck. And the graph well the graph is useless now and i have no idea how to fix that. no idea at all.
Any help would be great.
Cheers
To change the NUMBER OF ROWS, go to cell C13 and change the formula to
=SEQUENCE(E6*52)
The chart won't auto-adjust. So you need to adjust the chart's source data range to capture all rows.
Hey man, I really appreciate your contribution, this template is awesome, I am sure it will help me to plane my financial life, and also to pay debts earlier and create wealth.
Thank you!!!
how do i edit this to use months instead of years for term? i have a 90 month loan (7.5 years) that i am trying to use with this and it forces me to use 7 or 8 in years.