# What grade is 18 out of 20? — Grade Percentage to Letter Grade & GPA Calculator

> 18 out of 20 is 90% — an A on the standard scale (4.0 GPA) and an A− on the plus-minus scale (3.7 GPA). See the letter grade and GPA breakdown.

- **Answer:** 90% — A (4.0 GPA)
- **Category:** Education & Grades
- **Interactive calculator:** https://youcalc.com/en/education-grades/grade-percentage-letter/18-out-of-20/
- **Price:** Free, no sign-up required
- **Full calculator:** [Grade Percentage to Letter Grade & GPA Calculator](https://youcalc.com/en/education-grades/grade-percentage-letter/)
- **Pre-filled inputs:** `p=90`

| Metric | Value |
| --- | --- |
| Score | 18 / 20 |
| Percentage | 90% |
| Standard letter | A |
| Standard GPA | 4.0 |
| Plus-minus letter | A− |
| Plus-minus GPA | 3.7 |


## Overview

18 correct answers out of 20 is a 90% score. On the standard US letter-grade scale that is an A (90–100%), worth 4.0 GPA points. On the plus-minus scale, 90–92% maps to A−, earning 3.7 GPA points — so the letter can differ depending on which scale your school uses. Enter any percentage or fraction below to get the matching letter grade and GPA.

## Method

The calculation iterates through an ordered list of grade bands and returns the first band whose minimum and maximum percentage bounds (inclusive) contain the input score. The standard scale uses five bands (A, B, C, D, F) and assigns GPA points of 4.0, 3.0, 2.0, 1.0, and 0.0 respectively. The plus-minus scale uses thirteen bands (A+ through F) with GPA points drawn from the widely published US 4.0 system (source: back2college.com and calculator.net). Input is validated with Zod to reject values outside 0–100 before any lookup is performed.

## Related calculators

- [Test Grade Calculator](https://youcalc.com/en/education-grades/test-grade-calculator/)
- [GPA Calculator](https://youcalc.com/en/education-grades/gpa-weighted-grade/)
- [CGPA to Percentage Calculator](https://youcalc.com/en/education-grades/cgpa-to-percentage/)
- [Cumulative GPA Calculator](https://youcalc.com/en/education-grades/cumulative-gpa-calculator/)

## Sources

- https://www.back2college.com/gpa.htm
- https://www.calculator.net/gpa-calculator.html

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Interactive version: https://youcalc.com/en/education-grades/grade-percentage-letter/18-out-of-20/ · From YouCalc — https://youcalc.com