In America, Year 8 is equivalent to Grade 8, and students are typically 13 years old by August 31st of that year. This is the second, third, or fourth (and typically final) year of middle school. Below is a comparison of American and English (UK) school years and Key Stages:

• 11 to 12 years: Year 7 – Secondary School / Key Stage 3 / 6th Grade – Middle School
• 12 to 13 years: Year 8 / Key Stage 3 / 7th Grade
• 13 to 14 years: Year 9 / KS3 (or KS4 for 3 year GCSE programmes) / 8th Grade
• 14 to 15 years: Year 10 / Key Stage 4 / 9th Grade (Freshman) – High School
• 15 to 16 years: Year 11 / Key Stage 4 / 10th Grade (Sophomore)
• 16 to 17 years: Year 12 (6th Form) sometimes referred to as ‘lower 6th’ / Key Stage 5 / 11th Grade (Junior Year)
• 17 to 18 years: Year 13 (6th Form) often used as a route to University, sometimes referred to as ‘Upper 6th’ / Key Stage 5 / 12th Grade (Senior Year)

Its worth noting that the American and English school systems have similarities but also distinct differences.