The average child will graduate high school at the age of eighteen, following twelve years of primary and secondary school. You can determine the year your child will graduate by either taking their current age and subtracting it from eighteen, or their current year in school and subtracting it from twelve, and then using the result to estimate your child’s graduation year.

Calculating by Age

To determine graduation year by your child’s age, establish her age as of May in the current year. Then subtract this age from 18 and add the result of that subtraction to the current year. If your daughter is 9 years old in May of 2015, for example, you would subtract nine from 18. The outcome of 18 minus 9 is 9, so you would then add 9 years to the current year, or 2015 plus 9, to estimate that your daughter will graduate from high school in 2024. This method assumes that your child will have begun first grade by age 6 and will not have skipped any grades, as these adjustments could skew your calculations. For example, if your daughter begins school a year early at age 5, you would have to adjust your upper number down from 18 to 17, as at that pace she would graduate at the earlier age.

Calculating by School Year

You can perform the same calculation using your child’s current year in school and subtracting it from 12, the total number of school years before high school graduation. Then add this result to the current calendar year. If your son is in first grade in 2015, for example, subtract 1 from 12, resulting in 11. Then add this number to the calendar year, or 2015 plus 11, suggesting that your son will graduate in 2026. You must take into account any adjustments in the years of schooling required. If, for example, your son is for some reason must repeat a year of schooling due to missed graduation requirements, you would need to adjust your total number up from 18 to 19.