What is the smallest resolution to print 5x7?

Title says it. I have a file that I would like to get printed. Unfortunately it is only .7MP. What is the smallest resolution that would work for a 5x7?

Also, I have heard of ways to upscale a photo. Could this be an option?

I'd say just give it a go. However if you want some science, I can print as low as around 120ppi before noticing anything too dreadful, that works out at 840 x 600 pixels.

for a 5x7 that should be good enough...like Lowner said give it a try, at most you are out $.50

1 pixel, but it might be a bit underwhelming.

It depends on the photo, on the viewing distance, and on the eyesight of the viewers.

Lol good point armis.

Thanks for the replies! Im just gonna wing it and see what happens!