Below are the suggested numbers of megapixels to use for common print sizes.
If you crop your images increase the minimum suggested megapixels.
Today it is difficult to find a digital camera with less than 5 megapixels;
Some cameras will automatically reduce the size of the image when you switch between certain modes such as a high ISO
Print Size Megapixel Camera Pixel Size
4 x 6″ 2 megapixels 1600 x 1200
5 x 7″ 3 megapixels 2048 x 1536
8 x1 0″ 5 megapixels 2560 x 1920
11 x 14″ 6 megapixels 2816 x 2112
16 x 20″ + 8+ megapixels 3264 x 2468
Print quality depends on a number of factors, such as the visual quality of the original image, Printer type, ink, and the paper used.
If you plan on doing your own printing, use a photo printer and high quality photo paper for the best results.
©Peter Murphy 2010