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How Many Pixels Do You Need in a Digital Camera ?

R. Anderson 2/2009

Probably the most important feature to consider in selecting a camera is its megapixel rating. To better understand your needs, this article focuses on common print sizes and qualities that can be obtained with a given number of megapixels.

It is likely that you will share your images in many different ways. You may share them via email, an online album, your own website, or in print.

As using digital images to create quality photo prints typically requires the greatest number of pixels, the tables below help you understand the print quality relationships for megapixel dimensions. If you are not yet clear about pixel dimensions, print quality resolution standards, aspect ratios, and the impact of image cropping activity, you may benefit from reading the related articles at the bottom of this page.

Capturing image pixels in quantities that provide for quality printing leaves you with maximum image use flexibility as it remains easy to "downsize" images for other uses such as monitor display.

The tables below show the image pixels per inch (PPI) available for each inch of print dimension for common print sizes and megapixels ratings. The calculations reflect typical default cropping for print sizes and aspect ratios typical to digital cameras.

Default cropping is typically performed by enlarging a digital image to cover the aspect ratio of the intended print size, and then cropping the portion of the original image that extends beyond the area of the intended aspect ratio. This approach is often referred to as a "crop to fit" or "zoom and crop". The resulting maximum pixels per inch dictate the resolution quality of the photo print.

Key to Tables:
Darker Green - Photo Quality to Excellent print results (200+ PPI for smaller print sizes, and somewhat lower for larger print sizes).
Lighter Green - Very Good to Good print results (150+ PPI for smaller print sizes, and lower for larger print sizes).
Light Yellow - Good to Acceptable print results (print results less predictable)

Image aspect ratio of 1.33 common to Compact Digital Cameras

Megapixels	Pixel Array	4 x 6	5 x 7	8 x 10	11 x 14	16 x 20	20 x 30
1	1280 x 960	213	183	120	87	60	43
2	1600 x 1200	267	229	150	109	75	53
3	2048 x 1536	341	293	192	140	96	68
4	2240 x 1680	373	320	210	153	105	75
5	2560 x 1920	427	366	240	175	120	85
6	3032 x 2008	502	402	251	183	126	100
7	3072 x 2304	512	439	288	209	144	102
8	3264 x 2448	544	466	306	223	153	109

Image aspect ratio of 1.5 common to Digital SLR Cameras

Megapixels	Pixel Array	4 x 6	5 x 7	8 x 10	11 x 14	16 x 20	20 x 30
1	1225 x 816	204	163	102	74	51	41
2	1732 x 1155	289	231	144	105	72	58
3	2121 x 1414	354	283	177	129	88	71
4	2449 x 1633	408	327	204	148	102	82
5	2739 x 1826	457	365	228	166	114	91
6	3000 x 2000	500	400	250	182	125	100
7	3240 x 2106	540	432	270	196	135	108
8	3464 x 2309	577	462	289	210	144	115
9	3674 x 2449	612	490	306	223	153	122

It is quite certain that some camera manufacturers and professional photographers would disagree. However, unless you consistently perform aggressive manual cropping or often enlarge beyond 11" x 14", there is little reason to pay for more than roughly 5 or 6 megapixels of sensor capability. For more information on camera choices, visit Ebay's Digital Cameras Buying Guide.