What's the main difference between an iPhone 4 and an iphone 5?

What's the main difference between an iPhone 4 and an iphone 5?

The number after the word "iPhone"

The iPhone 4 doesn't have siri unless it's a 4s. The hardware & the body style is also different.

Screen size, the Iphone 5 has a bigger screen

Iphone 5 has a more powerful GPU and its screen is 7 % larger.

IPhone 5 is 4g/lte, it also has Siri, a larger screen, a more powerful prossesor and a better display

There's no main difference, rather there are a number of differences. The 5 has a larger screen, better hardware, 4G/LTE connectivity, supports more features of iOS 7, supports siri, will very likely support latter versions of iOS than the 4 will, and the 5 has a different cable connector than previous iPhones.

Anyone who says the only difference is the number, is a blind uninformed hater.

The iPhone 5 is different throne the 4 in every area.

Different SCREEN.
Different PROCESSOR.
Different CAMERA.
Different CHARGER.
Different BODY.
Different BATTERY.