What Percentage Is Each Letter Grade? A High School Teacher Breaks Down Common Scales
Last Tuesday, I was sitting at my kitchen table grading 9th grade midterms, a half-eaten bowl of pasta next to my red pen, when my sister texted me a screenshot of her 10th grader’s first high school report card. “Help,” the message said. “At his old middle school, an A- was 90 to 92. Here it says 88 to 90. He got an 89 in bio—so is that an A- or a B+? What percentage is each letter grade, anyway? Why can’t everyone just agree?”
I put my pen down, because I’ve gotten that question at least once a month since I started teaching 8 years ago, at three different public schools across two states. And honestly? Her confusion makes total sense. When I got my first full-time teaching job straight out of college, I used the +/- scale I learned from my student teaching placement for my first grading period, and ended up with 14 parent emails asking why half their kids’ A’s had turned into A-’s. I’d just assumed all schools used the same breakdown. I was very wrong.
Most parents my age grew up on the straightforward 10-point unweighted scale, the one we all remember: 90 to 100 is an A, 80 to 89 is a B, 70 to 79 is a C, 60 to 69 is a D, and anything below 60 is an F. No pluses or minuses, no fine print to sort through. But today, 9 out of 10 high schools and most middle schools use a weighted +/- scale that lines up with 4.0 GPA calculations, and those break down into two very common, very different versions.
The first is the one I use at my current school, aligned to the standard 4-point unweighted GPA scale: A+ is 97 to 100, 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 60 to 69, and anything below 60 is an F.
The second common version, which is what my nephew’s new high school uses, shifts the lower bounds of each grade down a couple points to curve for harder high school coursework: A+ is 97 to 100, A is 93 to 96, A- is 88 to 92, B+ is 86 to 88, B is 82 to 85, B- is 79 to 81, C+ is 76 to 78, C is 72 to 75, C- is 69 to 71, D is 60 to 68, and anything below 60 is an F. That’s why my nephew’s 89 jumped from a B+ to an A- when he changed districts—nothing changed about his work, just the rules. I’ve even seen small private schools where an A starts at 85, and some charters where A+ only starts at 99. No two districts are exactly the same.
When our district debated switching to the lower-shifted scale three years ago, we spent two full staff meetings going back and forth. Teachers who hated grade inflation said it would just hand out higher grades for the same work. Teachers who worked with overstressed honors kids said it didn’t make sense to drop a kid half a GPA point for missing two questions on a 100-point final. The scale we ended up with was a compromise that half the staff still doesn’t like. That’s just how it goes.
So what do you do if you’re staring at your kid’s report card right now, confused about where their percentage lands? The first step is the easiest: check the syllabus. I print my grading scale on the first page of my syllabus, linked on our class website and sent home to parents the first week of school. 99% of teachers do this. If you can’t find the syllabus, check the online parent or student handbook—districts almost always post the standard building-wide grading scale there. If it’s not in either place, send a one-line email to the teacher: “Could you share your percentage breakdown for letter grades this semester?” I’ve never met a teacher who minds getting that email. It’s way better than a panicked email two weeks before graduation asking why your kid’s GPA is lower than you expected.
If your kid just switched schools and their grades look wildly different than they used to, pull out both scales and map their percentages side by side. My sister did that after I texted her the breakdowns, and that one quick comparison took a ton of weight off both her and my nephew. He hadn’t suddenly gotten worse at biology, the scale just changed. If it goes the other way, and a 92 that was an A at the old school is an A- at the new one, that’s still just a rule change, not a drop in your kid’s effort or ability.
I had a parent come to parent-teacher conferences last year upset because her daughter was one tenth of a percentage point away from an A- in my class, which would have bumped her overall GPA up 0.2. I got it—she was applying to competitive colleges, every point counts. I offered her daughter an extra 2-point writing assignment to make up the gap, and that was that. If you’re in that spot, that’s a totally reasonable ask: just ask the teacher if there’s a small extra assignment to make up a tiny gap. Most will say yes for a kid who’s shown up all semester.
I texted my sister all this, put my phone down, and went back to grading midterms. I got to a paper that landed at 89.4, which is a B+ at our scale, just a hair under an A-. I left it as a B+, but added a note in the comment box that I’d accept a one-paragraph revision of the final body paragraph to bump it up, if she wanted. Then I closed my laptop, wiped the pasta crumbs off the table, and went to watch my 12-year-old practice her soccer drills in the backyard.
Grading scales will probably keep changing as schools adjust to new standards and new pressures, and there’s never going to be a universal agreement on what percentage equals what letter. But you don’t have to guess and stress about it. A two-minute check of the syllabus or a quick email clears up 90% of the confusion, and that one percentage point you’re worried about almost never matters as much as it feels like it does right now.
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