How many SIP calls at the same time using 256MB RAM

How many SIP calls using a calls codecs at 64Kb per call using a CPU with 256RAM

This calc is right: 256mb * 1024kb = 262144kb / 64kb = 4096 [Support for 4096 SIP calls]?

Is this right??? I’m confused. How to calculate how many calls at the same time using 256RAM?

Yes you are confused the Bandwidth of a call does not corrolate to the amount of ram used per call.

TBH with 256meg of ram you will be lucky to get Asterisk to handle more than one call reliably.