Grading Scales Explained

Updated July 12, 2026 · 9 min read

"What grading scale does your school use?" is a surprisingly complicated question. US schools mix four different systems, and the same 85% on a paper can turn into a B, a 3.0, or a "Proficient" depending on where a student sits. Here is what each system actually measures.

1. Percentage grading

The most direct system: points earned divided by points possible, times 100. Everything the QuickGrade calculator produces is a percentage. It is transparent and easy to average across assignments, but it says nothing about what the number means at your specific school.

2. Letter grades (A–F)

Letter grades map a percentage range to a symbol. See the full percentage-to-letter-grade chart for the standard scales. Letters are easy for parents to read on a report card, but they compress information — a 90% and a 99% both look like "A".

3. The 4.0 GPA scale

Grade Point Average converts each letter into a number so grades can be averaged across classes. On the traditional unweighted scale, A = 4.0, B = 3.0, C = 2.0, D = 1.0, F = 0.0. Plus/minus adds fractional steps (A− = 3.7, B+ = 3.3, and so on).

Some high schools use a weighted GPA that adds points for honors, AP, or IB classes — a 4.5 or 5.0 in an AP class instead of a 4.0. Colleges usually recalculate GPAs using their own formulas, so the exact weighted number on a transcript matters less than students think.

4. Standards-based grading

Standards-based grading (SBG) throws out percentages entirely. Instead of averaging assignments, teachers report proficiency on each learning standard — usually on a 4-level scale:

4 — Exceeds standard
3 — Meets standard (proficient)
2 — Approaching standard
1 — Below standard

SBG focuses on what a student has learned instead of whether they turned homework in on time. It is common in elementary schools and some progressive middle schools. The tradeoff: parents used to letter grades sometimes find it confusing, and mapping SBG marks to GPAs is not standardized.

5. Pass/Fail and Credit/No Credit

A simplified scale used for electives, senior projects, and college-level "audit" options. Only two outcomes matter: the student earned the credit or they did not. Often triggered when the underlying percentage crosses 60% or 70%.

How to choose a scale for your class

Follow the district first. Your report card software already assumes a scale. Fighting it just creates reporting headaches.
Match the audience. Elementary parents often want narrative feedback; high-school students track GPA.
Be consistent. Whichever scale you pick, apply it identically to every student in the class. Write it in the syllabus and refer to it every time grades come back.

For a quick refresher on how a raw percentage is even calculated, revisit our step-by-step grade calculation guide.