US.

Middle School and Jr. High vary depending on how the grades break.

When I was coming up it was this:

Grade School: 1-6
Jr. High - 7-9
High School - 10-12

But when I hit 9th grade, they changed it:

Grade School: 1-5
Middle School: 6-8
High School: 9-12

Slovakia.

If I am to translate it word-to-word:
Základná škola - Base school (so primary) (9 years) - split into 1st degree (1-4) and 2nd degree (5-9).
Stredná škola - Middle school (2-5 years based on field of study, 4 and 5 year fields are with graduation)

Get ready for a twist: Gymnasium (8 or 4 years) - 8 year gymnasium starts after 5th grade of primary school and 4 year after 9th grade. They also replace middle school. It's not that popular since you basically won't get any job without college with gymnasium. It's really just a preparation for college (literally "high school" (Vysoká škola)) (though perhaps better than middle school).

US. In my dialect, all three are different.

Middle school: 6-8

Intermediate school: 7-8

Jr High: 7-9

I attended an intermediate school that called itself a jr high, so I can understand the confusion.

Finland

0-5 year olds Kindergarten (voluntary)

6 y.o.'s pre-school (mandatory since 2018)

Grades 1-6 in comprehensive school are called "low school" (mandatory) Grades 7-9 in comprehensive school are called "high school" (mandatory)

Second degree years 1-3 (mandatory since 2021), you choose either "upper secondary (gymnasium)" or vocational school (or both).

And if you wish to study further university/uni of applied sciences. Basically everyone does their masters (3+2 years) if they choose uni. Uni of applied sciences is usually 3 years.

For my state in Australia its

Kinder Ages 3-5
Prep Ages 5-6
Primary School Ages 6-12, called Grade 1-6
Secondary/High School Ages 12-18, Called Years 7-12

After that you've got higher education choices via TAFE or University, theres no cut off ages for that.

School is mandatory from ages 6 To 17.

Romania. We call it primary (1-4), gymnasium (5-8) and lyceum (9-12). They come from French/Latin.

Latin is one of the roots of our language and we underwent a big pro-Latin cultural movement in the 19th century, while French also had a big cultural and educational influence.

Uk.
Its primary school then secondary school.
Primary school is 6 years "full time" (5/6 years old to 11/12 years old). There are pre-school and "reception" years.
Secondary school is 5 years, with an optional extra 2 years.
Anything beyond secondary school is uni/college/apprenticeship/life

I found secondary school year 6/7 to cover the majority of the foundation of 2 years at Uni (ie, maths, physics, chemistry had a huge amount of repitition before building on it and specialising).

Heres more info:
https://cdn.roostermarketing.com/wp-content/uploads/2017/08/school-years-1.png

In Denmark it's called Grade 0. 4-5 Grade 1-10. 6-15 Gymnasium (not sure why?) 15-18

Sweden

I don't believe we have the exact same stages as the US or UK, so I will do my best to explain it:

Grundskola - covers years 1 through 9 and is mandatory by law for everyone to attend.

Grundskola, year 1 through 3, student age 7 to 9 years - "lågstadiet", the frist three years in grundskola is called "lågstadiet", meaning the "low stage".

Grundskola, year 4 through 6, student age 10 to 12 years - "mellanstadiet", the middle three years in grundskola is called "mellanstadiet", meaning the "middle stage".

Grundskola, year 7 through 9, student age 13 to 15 years - "högstadiet", the last three years in grundskola is called "högstadiet", meaning the "high stage".

After grundskolan is completed we have "Gymnasiet" for another three years, this is where students really start to get to pick what direction they want to study towards, there are meny different programs to choose between, here are a few of the most common:

Samhällsprogrammet - Society studies, a generic program if you don't know what to study

Naturvetenskapsprogrammet - Natural sciences, a generic program likw above but you get dedicated science lessons, a good program that prepares you for just about any future studies.

Fordonsprogrammet - Vehicle studies, you like vehicles and want to work with them, you get to learn mechanics and learn how cars work, popular choice for those who have a hard time studying more theoritical subjects.

After gymnasiet you have a big graduation ceremony and party, everybody gets to wear the traditional hat (https://en.wikipedia.org/wiki/Student_cap#Sweden) and get to ride in the back of a birch covered lorry blaring music, this is called a studentflak and is part of the graduation party for most people.

After gymnasiet you basically have two options for further education: Högskola/Universitet or Kvalificerad Yrkesutbildning (KY), Högskola/Universitet is the more academic route forward, while KY is a trade school.

Canada:

Elementary: grades 1-8

High School: grades 9-12

UK:

1. Pre-school
2. Primary school
3. Secondary school (BUT my old HS literally has "high school" in the name so it's interchangeable with "HS")
4. College (16-18)
5. University

It can vary on area though. Some people have middle schools but I've no idea what ages they are since I've never seen one. Also, some UK people will hear me say "HS" and assume I'm American, not realising some secondary schools are called "high school"

To complicate matters more a "public school" is private.

ETA: I think US grades are off by one to UK "years". Though I've got into arguments with Brits about this I can only reference my own life. So our "Year 7" kids starting high/secondary school are 11yo. I believe that's 6th grade in the US?

In Brazil the names changed quite a bit across the years. I believe that the current ones are

• fundamental - 9 years (6yo to 14yo)
• médio (middle) - 3 years (15yo to 17yo)
• superior / universitário (universitarian) - typically 4~5 years, but it varies

The first two used to be called primeiro grau (first grade), segundo grau (second grade). And even further back, the primeiro grau was actually two, primário (primary - 4y, from 7yo to 10yo) and ginasial (gymnasial - 4y, from 11yo to 14yo).

In Mexico they are:

• Preescolar/Kinder/Jardín de niños (Preschool): ages 3-5 years old (can vary from state to state).
• Primaria (Elementary school): 6 years. Ages 6-12.
• Secundaria (Middle school): 3 years. Ages 12-15.
• Preparatoria/Bachillerato (High school): 3 years. Ages 15-18.
• Universidad (University, undergrad education): 2-8 years.
• Posgrado (Postgraduate education): Variable length. In my field a "Maestría" (Master's degree) is 2 years, and a "Doctorado" (PhD) is 4 years.

Republic of China, Taiwan

Kindergarten, Elementary/Primary 1-6 grade, Junior High 7-9, Senior high school 10-12, though most say year 1 junior(7th grade), year 1 senior(10th grade), then College/University/Tech University.

Some choose vocational high school after junior high, and most people from vocational high choose Tech University.

I attended a complete high school, means the whole secondary education combined, so we call junior high section 1-3rd grades and senior high section 4-6th grades🤣

Netherlands:

0.5: Kindergarten - ages 4 and 5
1: Basisschool Onderbouw (elementary part one) - ages 6, 7 and 8.
1.5: Basisschool Bovenbouw (elementary part one) - ages 9, 10, 11, sometimes 12.
2. Middelbare school (High school) - Ages 12 - 16/17/18 depending on what level of education you're going for.

0.5-1.5 is because they are usually all in the same school.

Canada (Ontario)

• preschool
• junior kindergarten, senior kindergarten, grades 1-6 | elementary school
• grades 7-8 | middle school (or also elementary if the school is K-8)
• grades 9-12 | high school

Texas, US. We called it Elementary (optional Pre-K, required K through 5), Middle (6 through 8), and High (9 through 12). They're called Primary and Secondary when filling out forms or legal documents.

Sweden, none of the above since we are not English native speakers. 😬

Grundskolan (mandatory for 6-15 year olds). Gymnasiet (optional for 16-19 year olds).

US. Growing up it was:

• Grade school / elementary school: Kindergarten through Grade 6
• Junior high: Grades 7 & 8
• High school: Grades 9-12
• Undergrad (typically 4 years)
• Grad school (duration depends)

From (the French-speaking part of) Belgium, 6 years of primary and 6 years of secondary. Nothing inbetween as that's already 12 years. Secondary usually happens within the same school although there are two divisions within it:
- programs are designed for three cycles ("degrés") of two years (D1, D2, D3)
- teacher's diploma follow a division in two "degrés" of three years : teachers for the inferior one (DI) have a bachelor and teachers for the superior one have a master. In the near future the diploma's will change but the distiction is mostly going to stay

In this latter sense, "inferior secondary" would be the equivalent to middle school and "superior secondary" the one for high school, although as I have explained it is not as separated as in the US, Italy, France or others. As someone who teach in the superior secondary "degré", I do usually introduce myself as a high-school teacher when talking to people from other countries.

US. We have kindergarten (start at age 6) followed by grades 1 through 12. How they are divided depends on where you live. Here are three examples I have seen:

K-8: Primary school
9-12: Secondary school or High school

K-5: Elementary school or Grade school
6-8: Middle school
9-12: High school

K-6: Elementary school or Grade school
7-9: Junior high school
10-12: High school

Anything beyond 12th grade is "post-secondary."

In the US, the names vary a lot by location. Even which grades are included can change based on the local population and how they choose to organize it. My wife and I went to school in the same state, maybe 45 minutes apart, and we did not have the same names or grade delineations.

For me, pre-school and kindergarten are each there own thing. Grades 1-3 were “elementary school”, 4-6 were “middle school”, 7-8 were “junior high”, and 9-12 were “high school”. We called them this based on the actual names of the school buildings. But even by the time I was in junior high, they started moving the 4th grade classes to the elementary school, so I’d assume kids in my own home town might say 1-4 is “elementary”. We didn’t have a “junior high” building. Grades 7 and 8 were still part of the “middle school”, but based on the changes in curriculum and the fact that they were held on a designated side of the building, it was colloquially referred to as “junior high”

In Russia it was for me just 1-11 grades with the last 2 being optional and the 4th one being suspiciously absent.

I went to school in the US state of Georgia. It was elementary (k-5), middle (6-8), and high (9-12). There was a school district next to mine that had a primary school that was k-2 and elementary was 3-5. There were other districts that had the 6th grade in elementary school, although that was becoming less common.

Ontario Canada Elementary, secondary but it depends on the school. Some are called high school, mine was called secondary school in the 90s but I think it's called a high school these days.

US. I had Elementary kindergarten-4th (5-10). Middle school was 5th-7th (/10/11-12/13). Junior high was 8th-9th(13/14-15). High school was 10th-12th (15/16-18/19).

US - specifically Michigan. The naming convention and splits most commonplace around me seem to be

Kindergarten - 4th grade | “Elementary School”

5th grade - 8th grade | “Middle School”

9th grade - 12th grade (referred to as Freshman, Sophomore, Junior, Senior years) | “High school”

But there is a bit of variance depending on district size. For example my school district downsized. So currently we have

Kindergarten - 6th grade | “Elementary School”

7th grade - 12th grade | “Secondary School”.

The former setup seems to resemble most of what other Americans would recognize.

Regarding “postsecondary education”, at least here, that specifically refers to any education past the standard 12 year education program, be it medical school or trade school or what we call college and many other places call uni/university.