Clink this link to download a copy of
Installing Inch Calc
For Excel 2013 and 2010
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.
For Excel for 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.
When you open the RLC.xlsx file you will be able to edit the link to find your copy of inch calc on your computer.