How the grade calculator works

GradeKind is an easy grade calculator built for teachers who need a fast, correct percentage and letter grade for a quiz, test, or assignment — including scores with partial credit. Everything below describes exactly how the calculator gets its numbers, so you can trust the result and explain it to a student or parent if asked.

What the calculator does

Enter a score in either Questions mode or Points mode, and GradeKind returns a percentage, the equivalent letter grade under your chosen grading scale, and a chart showing every possible score at that total. It runs entirely in your browser: there is no sign-up, and no student names or scores ever leave your device.

Using Questions mode

Questions mode is for grading where every question is worth the same amount — a typical multiple-choice quiz, for example. Enter the total number of questions, then enter either the number the student got correct or the number they got wrong; GradeKind works out the other value automatically. Because every question counts equally in this mode, only whole numbers are accepted. If you try to enter a decimal — say, a question worth half credit — GradeKind will direct you to Points mode instead, rather than rounding your answer for you.

Using Points mode

Points mode is for anything with partial credit, uneven point values, or a decimal score. Enter the total points possible for the assignment, then enter either the points earned or the points lost. Points mode accepts decimals up to four places (for example, 12.3456), so it comfortably handles half points, quarter points, and rubric-based scoring.

How partial credit works

Partial credit is just a decimal value in Points mode. For example, a 20-point assignment where a student earned 16.5 points produces the same 82.5% whether you enter "16.5 points earned" or "3.5 points lost" — GradeKind treats those as exactly equivalent, down to the last decimal place, because Earned + Lost always equals the Total.

How percentages are calculated

The underlying formula is simple:

Percentage = Earned \u00f7 Total \u00d7 100

where Earned = Total \u2212 Lost when you enter points or answers lost instead of earned. The calculator works with your entered numbers directly, using exact decimal arithmetic rather than general-purpose floating-point math, specifically to avoid the small rounding errors that can otherwise creep in near grade boundaries.

How letter-grade thresholds and rounding work

Each grade in your grading scale has a minimum percentage — for example, the default scale awards a B for 80% up to just below 90%. GradeKind compares your exact, unrounded percentage against those thresholds. The percentage shown on screen can be displayed as a whole number or with two decimal places, but that display choice never changes which grade is assigned — a score of 89.995% will always be a B under a 90% A-threshold. Near a boundary, extra digits are shown to avoid a misleading "90.00%" display. This keeps the calculation trustworthy even right at a boundary.

The default A/B/C/D/F scale shown in the calculator is an editable example, not an official standard for any particular school or country — you can change every threshold and save your own scale.

Frequently asked questions

← Back to the calculator