InchCalc Add-in for Excel


InchCalc is an Add-in for Microsoft Excel that makes it possible to do calculations in feet and inches. It is handy for architects, builders, and carpenters.

Here is an example spreadsheet showing how to sum a list of dimensions...

Example showing how to sum measurements using InchCalc

Here is what the formulas look like for the above spreadsheet...

Example showing the formulas in the above spreadsheet

Quick Start

  1. Click here to download the InchCalc.xla add-in file and save it to a folder on your hard drive.
  2. Install the InchCalc Add-In...

For Excel 2010-2016

  1. Click the File on the menu bar, and then click Options in the left panel.
  2. Click the Add-Ins category.
  3. In the Manage box, click Excel Add-ins, and then click Go.
  4. Click Browse, and then locate the InchCalc.xla add-in file that you downloaded above.
  5. Quit out and reload Excel. Now type =i2s(12) in the first cell and press enter!


Microsoft changed how add-ins work in an update, so now you need to also follow the trust settings in the FAQ below!


For Excel 2007

  1. Click the Microsoft Office Button Office 2007 Logo, and then click Excel Options.
  2. Click the Add-Ins category.
  3. In the Manage box, click Excel Add-ins, and then click Go.
  4. Click Browse, and then locate the InchCalc.xla add-in file that you downloaded above.
  5. Quit out and reload Excel. Now type =i2s(12) in the first cell and press enter!

For Excel 2000-2003

  1. On the Tools menu, click Add-Ins.
  2. Click Browse, and then locate the InchCalc.xla add-in file that you downloaded above.

For Excel 2004 Mac

  1. On the Tools menu, click Add-Ins.
  2. Click Select, and then locate the InchCalc.xla add-in file that you downloaded above and click Open.


InchCalc is now installed. The functions i2s() and s2i() should be available just like any other Excel functions.

Click here to download and open the demo workbook InchCalcDemo.xls in Excel and play with it! There are three sheets in this workbook, be sure to look at them all.

How it works

InchCalc adds two new functions to Excel;

s2i() converts a displayable string showing inches and feet into a a number of inches. The number of inches can be used in formulas and sums. For example, the s2i() of 2' 6" is 30 because 2 feet + 6 inches = 30 inches.

i2s() converts a number of inches to a displayable string showing feet and inches. For example, the i2s() of 145 is 12' - 1".

s2i() and i2s() are inverse functions, so i2s( i2s( 25 ) ) = 25.

Typically you will set up your spreadsheet so you can enter all your measurements into a column of cells, then convert those measures into their equivalent inches in an adjacent column with s2i(), then do all your calculations in inches, and finally convert the answer in inches back to a displayable form with i2s(). The best way to understand this is just open the sample spreadsheet and just play around with changing the values and formulas. It is very simple.

The i2s() function optionally supports a couple of different formats for the generated string. You specify which format you want by adding a second argument to the i2s() function call.

 i2s() Formats
(default) f'_-_i_n/d"
1 f'-i_n/d"
2 f'_i_n/d"
3 f'i_n/d"
4 f'_i-n/d"
5 f'i-n/d"

f=feet, _=space, i=whole number of inches, n=numerator of fractional inches, d=denominator of fractional inches


Additionally, the i2s() function supports a second optional parameter that when specified as '1' suppresses the conversion of inches to feet, so the formatted value only includes whole and fractional feet.


The formatting demo spreadsheet below shows how different values look with the different formats...

Formating examples

The s2i() function is pretty flexible and will accept almost any reasonable combination of feet, inches, fractions, decimals, spaces, and dashes. Note that double quote character is a bit problematic in Excel since they usually surround a text string. The easiest way around this is to put each dimension in its own cell and reference those cells in your calculations rather than trying to type the dimension directly inside a formula. If you have to put a dimension inside a formula you can use the function char(34) to generate a double quote. For example, s2i( "2' 6"+char(34) ) = 30. Or you could use the i2s() function to generate the string.

Another Example

Here is an example of how you might do area-based costing calculations with InchCalc...

Example of doing area costing calculations with InchCalc

..and the formulas used...

The formulas used in the area-costing example 


If you have trouble downloading the add-in file and the sample spreadsheet from the links above, they are both inside the ZIP file below...


A couple tips form other InchCalc users. Send in yours!


Q: When I pull up the sample spreadsheet, all I see is #NAME everywhere!

A: First make sure you installed the plug-in according to the instructions above. If so, try quiting out Excel and Restarting it. Next check your Macro settings. Try setting them to the most permissive possible just to see if that fixes it. If so, you can move then set the back to the most restrictive setting that still works.

6/16/17 - Helpful advice from David Meaux:

I figured it out.


Windows 10 is really picky, apparently.  I opened both spreadsheets, then went into VB and copied the module from yours into the other one. 

Worked fine.

3/20/2018 - Helpful advice from Jessye Ford:

I was having some mad issues with your program running in Office 365 2016, here is an excerpt from a forum that I came across while trying to figure out what was going on:

down voteaccepted

This problem results from security patch in KB31152, released in July 2016. According to private communication with Microsoft software engineers:

"With this update, we changed the behavior of Excel so that it will not load certain file types (including .xlam) when they are untrusted. The easiest workaround is to find the add-in that is causing you trouble, right-clicking on it in Windows Explorer, and checking Unblock"

An easier approach is to simply place the add-in in a Trusted Location (in Excel, go to File > Options > Trust Center > Trust Center Settings > Trusted Locations), such as the following folder, and load it from there:

C:\Users\%USER NAME%\AppData\Roaming\Microsoft\Excel\XLSTART

Unfortunately, Microsoft failed to clearly document this major, "breaking" change (as of this writing), leaving probably hundreds of thousands (millions?) of Excel users wondering why their add-ins are not loading. They did, however, bury some useful information about this issue in a blog post:


Q: Why do I get values with lots of extra trailing decimal digits when I do conversions like =i2s(144.1)?

A: This is an inherent problem in Excel. Try typing the following formula into Excel (any Excel spreadsheet, InchCalc *NOT* required);


You might be very surprised to see that the answer is NOT zero.

I could make InchCalc hide this problem from you by rounding in the incoming inches to, say, 10 decimal places but I generally prefer to have things fail quickly and explicitly rather trying to hide the problem only to have it show up unexpectedly in a seemingly unrelated cell.

You can read the Microsoft Knowledgebase article here;

Ultimately the solution is to not use decimals unless they are an even power of two in the denominator (0.125 is ok, 0.100 is not). 

This is not too much of a problem for InchCalc measurements since most people by convention specify inches in fractions since that it how ruler and other measuring tools work. Note that decimals are ok, as long as they are halves, quarters, eighths, sixteenths, etc. rather than tenths.

Maybe someday Excel will permanently solve this problem by adding a Binary Coded Decimal data type. Most modern computer programming languages have this (in Java it is called BigDecimal). It is slow, but you never get decimal error creep.

Q: Does InchCalc support OpenOffice?

While it certainly would be possible to make a version of InchCalc that works with OpenOffice, I've found that most professionals use Excel. Additionally, OpenOffice's documentation for creating add-ins is not great, so it would be more difficult that it should be. That said, if there were enough people who really wanted it, I be happy to put in the effort.

Q: When I try to download the spreadsheet files, all I get is a text file full of garbage. What Can I do?

A: There are lots of things that can get in the way of you directly downloading Excel spreadsheets. These are usually put in place to block viruses. Try downloading the ZIP file instead, then extract the files form the ZIP onto your hard drive and open them from there.

Q: Is it possible to convert mm into feet & inches?

A: To convert, say, 1000mm into inches and feet, you could put the following to a cell…  

 =i2s( 1000 * 0.0393701 )  

…which gives 3' - 3.3701".

(Note that there are 0.0393701 inches in a mm)

Revision History


  • Initial release.


  • New version of InchCalc.xla adds compatibility with Mac Office 2004.
  • Changed behavior of i2s to add a separator when the whole number of inches is zero
  • Added optional parameter to i2s() to suppress conversion to feet so all results are shown in inches.
  • Changed the is2() function so that a zero now always shows up in the inches field. Before, the inches were suppressed in cases where there was just a fractional number of inches.
    Example: i2s(13.5) used to return "13' 1/2"" but now returns "13' 0 1/2".
  • Added instruction for Excel 2010.
  • Added step to shutdown and restat Excel after installing the AddIn. Don't know what, but some people need to do this for it to work.
  • Added question to FAQ with advice about what to try when you get #NAME everywhere.
  • Added FAQ on mm conversion.
  • Updated instrcutions to include Excel 2016


If you have any problems or questions, you can email me at...

InchCalc Support Email address 

InchCalc is (c)2006 Joshua Levine. InchCalc is free to use. If you want to modify or sell InchCalc, or include it in your product, please email me and we can work something out.