Grades, Years, Key Stage Comparison

I have been wondering for a long time how the US Grades relate to the new British School Year system, and in turn how these correspond to the English National Curriculum Key Stages. I am sure that many of you, particularly homeschoolers in England & Wales perhaps wanting to buy curriculum from the US, will have been in the same position and so, hopefully in order to clear up the confusion, I present my understanding of how the three relate and approximately which ages fit where! Please note that this table represents a comparison by age - the level of work or education going on at each of these ages will not necessarily compare between the two.

(Do not take my word as law however! Please do let me know if any of this is wrong! I'm especially not 100% sure of where the Key Stages fit in, so may up-date that section at a later date).

I know, of course, that in the US, children who do not attain the necessary Grades at the set age will be kept in a lower Grade than their peers, and students with above Grade average may advance to higher Grades (I have it on good authority, however, that "advancing students is rarely done and is usually done at the request of the parents. However holding back (flunking) of students is much more common. Sometimes the more advanced students take one or more harder classes if available in the specific subject, though remedial classes for those behind are more common".) Whereas, in England, peer age groups are kept together regardless of ability, and the teachers attempt to cater for advanced or 'special needs' students alongside 'average' students.

Please note that, whereas In the US, different States have different requirements, in England, none of this is mandatory: you are not in any way required by Law to keep to the National Curriculum. I present this information purely for reference.

US Grades/ British School Years/ Key Stage/ Age Comparison Table
US Grade System	Level	Age	British School Year System	Welsh & English National Curriculum "Key Stages"
Nursery/ Pre-K	-	0-4	Pre-school	National Curriculum for Pre-school: "Desirable Learning Outcomes"
Pre-K	-	4-5*	Reception	"Baseline Assessment"*
Kindergarten	-	5-6	1	Key Stage 1
1	Elementary	6-7	2	"
2	"	7-8	3	Key Stage 2
3	"	8-9	4	"
4	"	9-10	5	Key Stage 3
5	"	10-11	6	"
6	Junior High	11-12	7	"
7	"	12-13	8	Key Stage 4
8	"	13-14	9	"
9	High School: Freshman	14-15	10	GCSEs
10	HS: Sophomore	14-16	11	"
11	HS: Junior	16-17	12	GCE 'A' Level
12	HS: Senior	17-18	13	(at 'Sixth Form' or College)
Junior College	Community College	18-	Various	Higher Education at
courses	Technical College or University	-21+	courses	University, Technical College etc.

* As I understand it, in England, 'education' (commonly confused with school attendance, or even 'formal education') must legally be started no later than the term of the child's 5th birthday (Whereas in the US, school begins at age 6, so pre-K & Kindergarten are not compulsory) and may end "no sooner than the child's 16th birthday", although the child may continue to receive State education at school or college until the completion of the school year in which s/he turns 18.

* Baseline Assessment takes place upon school entry. Basically, the teacher has to assess where the child is academically, to what extent s/he has covered the 'Desired Learning Outcomes' pre-school, and what is lacking.

I hope all this makes sense; however,
if this table contains errors
or if you have anything to add,
please let me know!