Instructions
Decide on which free spreadsheet program to use. Open Office Calc, Google Docs and Gnumeric are all high-quality, easy-to-use free programs. Each of these programs allows you to create and save complicated spreadsheet documents.
Prepare the spreadsheet for organizing a coin collection. Make columns for year minted (mint mark can be marked in the same column as year minted), grade and value. You can choose to include all countries, denominations and special sets in this initial spreadsheet, or you can make different spreadsheets for each of these categories.
Take detailed inventory of your coin collection. The easiest way to do this is by inventorying each type of coin, one at a time. You may need to do some research to come up with approximate grades and values for each of the different types of coins you have. Put this information straight into the spreadsheet program you are using in order to avoid having to needlessly copy information.
Play with your document. Spreadsheets allow you to organize information via rows and columns. This allows you to look at your entire collection organized by year, condition and overall value. By looking over the document or documents you have created, you can get a complete idea of the size and value of your coin collection.