250 Mb G729 how much mobile call time a month


I like to use SIP account with mobile internet on the road in Europe.
But data is very expensive in Europe and I have only 250 Mb a month.
I know that G729a is about 8Kbps that would nearly 60 hours call time,but that’s not the reality i guess.
How much overhead and keep alive traffic do in need to calculate for a month.

I have no qlue in that , I don want to get a huge bill.


Try a bandwidth calculator here:

You’ve got to add overhead on top of the base RTP size.

Thanks howdy

I looked at this calculator bud Iḿ not that technical and my main language isn’t english so hard to understand.
Still i gues this calculator doesn’t tell me the bytes I use without calling.
So for example one month i don’t make any calls how many Mb do I use for registering and keep alives.

Sorry, I’m not able to answer that.

Does your provider allow you to send an SMS to see what your usage is?

You could check your usage, turn on the client, run it for one day with no calls, and then check your usage again. Or, run it for 1 hour and do the same.

I have to decide to set this up or not.
Do I buy 250Mb or 1Gb, it’s 25 euro a month more :cry:
Problem with the telco’s is you hang for a year with that.

Let’s say we used the calculator for one incoming / outgoing G.729 call over SIP. It’s going to tell us that it’s using 47.26kbit/s for a call, not counting SIP overhead. Can’t calculate that exactly because we’ve no idea what your client is going to be doing for BLF or voicemail or anything like that. Don’t even try. Let’s ignore it for now.

If you’ve got 250mbit per month, and each call uses 47.26kbit/s, then you’ve got 5416 seconds of calling you can make, or 90 minutes. Toss in overhead at a swag and call it 60 minutes of calling per month, using G.729.



Sorry my mistake bites and bytes.
It’s 250MB so it would be 8 times more is it ?
Nearly 500 minutes ,then it would be worth-it 0.07 eurocent a minute normaly 0.40.

Thanks a lot


Yes, should be 8 times as much in that case.

Good luck. :smile: