What Percentage Is Each Letter Grade? A Teacher Breaks Down Common K-12 Grading Scales
Last Wednesday, I wrapped up three hours of parent-teacher conferences at my high school, tossed my stack of graded quizzes and rubrics in the trunk, and came home to find my 10th grader, Lila, leaning against the fridge holding her first quarterly high school report card. She poked at the cold mac and cheese I’d left on the counter an hour earlier, and pushed the folded paper toward me. “My bio teacher gave me an A minus,” she said. “What does that even mean? Is that an 89? A 90? I can never remember what percentage lines up with each letter.”
As a 12-year high school math teacher, I wasn’t surprised. I’d gotten that exact question from three different parents just that afternoon. One mom whose daughter transferred from a neighboring district couldn’t wrap her head around why her 89 was a B+ in my class, when it had been an A- at her old school. Another dad wanted to double-check that his son’s A+ wasn’t just a “participation trophy” grade, but actually reflected a percentage above 97. Letter grades are how we communicate progress to parents and kids, but almost nobody talks about how much the percentage ranges behind them can change from school to school, or even district to district.
I pulled the crumpled copy of our district’s grading policy out from behind the grocery list, held on by a dinosaur magnet Lila made in 7th grade art, and walked her through the most common scale most U.S. public schools use today: the 10-point scale. That’s where it breaks down like this: A+ is 97 to 100 percent, A is 93 to 96, A- is 90 to 92. B+ is 87 to 89, B is 83 to 86, B- is 80 to 82. C+ is 77 to 79, C is 73 to 76, C- is 70 to 72. D+ is 67 to 69, D is 63 to 66, D- is 60 to 62. Anything below 60 is an F.
That’s the standard most people learn, but plenty of schools tweak it. Some don’t give out A+ at all, so their A range starts at 93 and goes all the way up to 100. Other schools use a 7-point scale, most often private schools or schools with a lot of advanced coursework, that looks totally different: A is 93 to 100, B is 85 to 92, C is 77 to 84, D is 70 to 76, and anything below 70 is an F. I saw that cause a big mix-up last year when a student transferred to my school from a local private school that used the 7-point scale. His parents were thrilled he’d earned a B in first semester algebra at his old school, and assumed that put him solidly in the 80s, on track for honors geometry. When we converted his grade to our scale, that B was actually an 88, which would be an A on our 10-point scale, so we were able to move him up to honors right away. That confusion could have held him back a whole year if we hadn’t caught it.
Another point of confusion is how letter grades convert to GPA, which is what most parents and kids care about for college. On the standard 4.0 scale, an A+ and an A both usually count as 4.0, while an A- is 3.7, a B+ is 3.3, a B is 3.0, and so on. A handful of schools give extra weight to A+ grades, counting them as 4.3 to reward students who score above 97, but that’s much less common than people think. For weighted GPAs in honors or AP classes, the same percentage ranges apply, you just add an extra 0.5 or 1 point to the final GPA score depending on the school’s policy.
After I went through all that with Lila, she checked the percentage posted on her bio teacher’s Canvas page. Her average was a 91, which matched up to the A- perfectly, and she shrugged, folded the report card back up, and went back to editing a TikTok for her group project. That’s how it usually goes, honestly. Most of the time, the confusion around letter grades isn’t about a kid failing or a teacher being unfair. It’s just that nobody stopped to tell you that the scale changed when you moved districts, or the grading policy is buried three layers deep on the district website.
The best thing you can do if you’re confused is simple. First, pull up your district’s current student handbook online — it’s almost always under the “parents” or “student resources” tab, and it will have the exact percentage breakdown for every letter grade used in the district. Don’t rely on what you remember from when your oldest kid was in high school five years ago; districts do update their scales every now and then. Second, if your kid transfers to a new school mid-year, email the guidance office and ask for a copy of their grading scale before you start panicking about a surprising grade. Third, if you still can’t find it, just email your kid’s teacher. Most of us would rather answer a quick question than have you stressing for a week over a grade that’s just a difference in scales.
I still get this question every quarter, from new parents and experienced ones alike. There’s no one universal answer that fits every school, which is why the confusion keeps popping up. Right now, Lila’s report card is taped to the side of the fridge next to her soccer practice schedule, and the crumpled grading policy is still behind the grocery list. It’s not a big, dramatic problem. It’s just one of those small, unspoken gaps between school and home that takes five minutes to fix, if you know what to ask for.
Please indicate: Thinking In Educating » What Percentage Is Each Letter Grade