There are are two calculators below.
What do they do?
Let's say a friend gave you a box of 16" x 20" paper.
How may pixels do you need to make a print at a resolution of 300 pixels per inch?
To get the answer, use the Print Size to Pixels Calculator.
Let's say your camera is set to record photographs that are 4,000 x 6,000 pixels.
What size print can you make at a resolution of 300 pixels per inch?
To get the answer, use the Pixels to Print Size Calculator.
If you don't know the pixel dimensions of a photograph, open it in Photoshop Elements.
Go to Pixel Dimensions.
If you don't have enough pixels to make a print at your desired resolution, add some more pixels.
This is called resampling or interpolation.
In Photoshop Elements, do the following.
1) At the top of your screen, go to Image > Resize > Image Size.
2) Make sure Constrain Proportions and Resample Image are selected in the lower-left corner of the window.
3) In the menu at the bottom of the window, change Bicubic to Bicubic Smoother.
4) Highlight the width value, and enter the value you need.
The value you use is the width (horizontal) value from the calcultor.
The height value changes automatically when you enter a new width value.
5) Click OK.
Go to Resampling.