One question I get asked a lot by friends and family is "how big can I print this digital photo?" My answer is always "it depends," which then requires a lengthy discussion of pixels per inch and viewing distance and other mundane topics.
So, I put together a little Excel spreadsheet that should help you determine what size prints you can make with reasonable quality based on the size of the digital photos you have. You can get it here or click on the screen capture below (you have to have Microsoft Excel to use the file).
I've based the calculations employed by the spreadsheet largely on my own experience and preferences, so if you have a more or less critical eye than is typical, you might differ with some of the recommendations the guide offers. In that case, leave me a comment and I'll tell you how to change the PPI (pixels per inch) guidelines used in calculating the ratings.