Developing iOS app for iPhone5 (4 inch), How it will look on iPhone4 (3.5 inch)?

Developing iOS app for iPhone5 (4 inch), How it will look on iPhone4 (3.5 inch)?

I am developing an iOS app for iPhone5 (4 inch), How it will look on iPhone4 (3.5 inch)?
Or
anything else you can suggest
Thank you!!!