How much RAM is needed? 

Source: Google

Are you going to buy a new smartphone? And if you're confused "How much RAM is to choose?".

Don't expect the whole RAM of your mobile is free to use. Some part of your RAM is used by OS(Android), System UI, Keyboard, & Google etc..... 

For example: I have a Mobile of 4GB RAM, I can use maximum of 1.5GB. Because the remaining is used by Android OS, System UI, Google Play services, Google etc...

Categories: 
1) Normal Use

            For general use like watching YouTube, Facebook, Instagram, & browsing internet 4GB of minimum RAM is required, better if more.

2) Gaming

Source: Google

     Generally gaming needs more RAM for heavy games like PUBG Mobile, Call Of Duty Mobile, Fortnite Mobile,... So, minimum of 6GB/8GB is recommended.

3) Multitasking

Source: Google

Multitasking like editing videos & images, using multiple apps simultaneously needs a minimum of 6GB RAM.