Technical | iPad/ iPhone Pixel Dimension

Before starting to design the app I must find out the size screens I will be working with. Below are the specs for resolution and pixel density:

iPhone 5s  -      1136x640 resolution at 326 pixels per inch

iPad Air     -      2048x1536 resolution at 326 pixels per inch 

These are the guidelines I need for starting out my design. They will give me canvas sizes and ppi.