I went to school in New Zealand and Australia, and my kids attend an Australian school. For many reasons, I found the NZ system better than the Australian one.
Primary school - grades 1 - 6 (junior 1 - standard 4 in my day). Age 5 (or very occasionally age 6) - 10/11 years.
Intermediate school - grades 7 - 8 (forms 1 - 2 in my day). 10/11 - 12/13 years.
High school - grade 9 - 13 (forms 3 - 7 in my day). Age 12/13 -17/18 years.
Kids must be enrolled by their 6th birthday, but can start anytime in the year between their 5th or 6th birthdays. I love this system as it gives parents the chance to make the best decision for their child depending on their child's development. Most people I know start/ed school on the first school day after their 5th birthday. School is compulsory until age 16.
When I was young, kindergarten (ages 3 - 5) was free and maybe 50% of children attended. Very rarely affiliated with any school. Not sure about these days. In some (primarily rural) areas, primary/intermediate or intermediate/high school were combined into one school.
Qld, Australia (based on when my children started).
Pre-school/prep - optional, but probably 99% of kids attended. Usually attached to primary school. (Age 4/5 - 5/6). Was 5 days a fortnight, now 5 full days each week.
Primary school - grades 1-7 (age 5/6 - 12/13).
High school - grades 8-12 (ages 12/13-17/18).
This will change in 2015 so that year 7 will now be in high school . A few years ago the starting age was changed so that now all students start school at least 6 months older than they would've been prior to that. This means the minimum starting age for prep will be 4 1/2, as opposed to my DS2 who was just 4 when he started and turned 5 as preschool finished (and will be 16 when he leaves).
There is only 1 intake a year, which puts pressure on parents to send their child either before they are ready (and then repeat later), or a very school child ready has to wait up to a year to start (as was the case with DS1; missed cut off by 3 days, despite fact that school year didn't even start till a month after that). I realise this problem is prevalent in many countries, not just unique to Australia.
School year must be 180 days
I've been wondering about this. On some of the other US based boards I frequent there's often talk of school being extended because it was shut for X days or weeks due to snow. So, if school was to end on 30 May, but it had been shut for 5 days because of snow, would the students then be expected to come along to school till 6 June? For a whole host of reasons, I can't even begin
to imagine the outrage, protests and refusal to actually do it if it was even suggested
here, and if that was my child, he'd be finishing on 30 May, full stop, especially if I'd made travel plans. Actually, now I think about it, a while ago there was talk on the news of introducing Saturday detentions and the backlash was instant and unanimous: not happening; so I can't see extending the school year would get any support whatsoever.
Where I live the school year finishes in December, (and it seems as though the entire country stops between mid December and mid January), so there's not a lot of leeway to extend things with Christmas as a fixed point, anyway. Schools here have closed for the odd day here and there, or even a week or more due to floods, but there's never, ever, been talk of extending the school year to make up for it. Teachers/schools simply adjust the programme to incorporate the shorter time frame and get on with it.