In Sydney compulsory schooling starts at age 4-5 depending on their birthdate. General cut off date for public (free government school) schools is July 31st. So come January and the new school year, your child would start school if they turn 5 by the 31st of July. They may already be 5 (August-Jan birth) or be only 4 turning 5. It is also acceptable for parents to choose to hold their child back a year if they are close to the cut off date and the parents feel they wouldn't be ready for school. Private and Catholic schools may have their own cut-off dates for starting school.
Prior to starting school, parents can choose (most do) to send their child to Pre-school which is categorised as Early Stage 1. This can be a dedicated pre-school for 3-5 year olds to prepare them for "big school". Some primary schools have a pre-school attached to the school (some government subsidised if attached to a public primary school esp in lower socio-economic areas and are very cheap eg $2 per day), but the children don't wear a uniform and they rarely join in whole school events eg assemblys. Often the days are half days or the children only attend a few days a week.
The other option is if your child is at a day care centre because the parents work. These also offer a pre-school program/school readiness program and have links with the local public schools.
The first year of compulsory schooling is Kindergarten. Although this is also categorised as Early Stage 1 for curriculum purposes, it looks/acts for all intents and purposes as primary schooling. They wear a uniform, attend school 5 days a week (usually staggered at the beginning of the year as an introduction, but only for a few weeks), arrive and leave when the rest of the school does, have homework, are involved in school assemblies etc.
Then you have years 1-2 which are categorised as Stage 1.
Years 3-4 = Stage 2
Years 5-6 = Stage 3
Some schools may still break the school into infants (k-2) and primary (3-6) but this is usually for practical reasons eg assemblies, sports days etc.
Schools may also have composite or staged classes which can be graded (eg year 3 and 4 children in classes together based on ability would be called a 3/4 class) or may just stick with classes based on age eg year 3 class. The school may also choose to mix the children up for maths and english based on ability eg all the high ability year 3 children come together for maths and english but for the rest of the school day/other subjects they are with their normal mixed ability class.
After year 6 children go to High School which is stages 4 (yrs 7-8), 5 (9-10) and 6 (yrs 11-12). Again, these are referred day to day by years 7-12 rather than by stage. Stage 6 is optional but the majority of children are expected to do this stage as it gives them their Higher School Certificate (HSC) and allows them to apply for university. Otherwise they just receive a School Certificate if they leave in year 10 - apprenticeships or tafe (alternative/practical education compared to university) are the usual reasons people leave at the end of year 10/Stage 5.
Private schools (big bucks fees!) often cater for k-12 meaning your child is at the same school until they graduate to go into the work force or attend university. Non-Private catholic schools and public schools mean your child goes to 2 different schools - primary then high school.
Hope that helps!
Monique (teacher and parent)