When we got our NBN set up, we got the technician to test the speeds saying we could get a maximum speed of 144mbps which would be great, then once we had the NBN hooked up we were getting speeds of around 10-15mbps. We then called the optus support line to see what was wrong and what we were supposed to be getting in terms of speed. The optus support person said we should be getting downloads of 25 MBps, he even corrected himself saying "you will get 25 megabits, bytes, megabytes of download speed." So im sorta confused as to why we never got our speed we were told about?
The correct unit is megabits per second (Mbps). Which plan are you on and how are you doing the speed test?
As our community members have mentioned, we'd really need to grab a few more details. We have made a recent update to our NBN speed guide which you can find here. Speeds are access technology specific. Depending on the type of technology, your maximum attainable speed may differ. For example speeds of an FTTN service (fibre to the node) are dictated by the length of copper running from the node to your Network Boundary Point.
There are also other considerations such as end user equipment, internal wiring and available bandwidth (based on CVC capacity that the ISP has purchased).
If you could send through your post code and street name - Peter can give you some sort of general indication of you can expect.