Grade Boundary Maker

A grade boundary is the minimum score required to earn a particular grade. If your scale says a B is 80 to 89, then 80 is the lower boundary for B and 90 is the lower boundary for A. Boundaries matter because they make grading transparent and defensible. A student who scores 79.5 deserves to know in advance whether your policy is to round up, hold the line, or apply a soft buffer near each cut score. Publishing your boundaries at the start of a term, ideally in the syllabus, also protects you from individual grade disputes by making the rule, not the marker, the source of the decision.

Letter grades (A through F) are the default in most US K-12 and university gradebooks because they roll up cleanly into a GPA. Percentage bands with named levels (Excellent, Proficient, Approaching, Below) work well when you want to describe performance qualitatively without committing to a letter or GPA value, common in workshops, short courses, and professional training. A standards-based 4-point scale (1 = beginning, 4 = exceeds) is the dominant model in standards-aligned K-8 classrooms and increasingly in high schools that have moved away from averaging. Pick the one that matches what your school requires on report cards. If you have a choice, match the cognitive frame you want students to bring to feedback.

The traditional US scale uses a 90-80-70-60 rule (A starts at 90, B at 80, and so on) but there is no national mandate and many schools use tighter or looser bands. A common variation is the 93-85-77-70 scale, which raises the A threshold and matches the more selective grading found at competitive high schools and universities. If you teach a course with frequent low-stakes formative assessment, a stricter scale rewards consistency. If you teach a course with high-stakes single-shot exams, a more generous scale absorbs measurement error. Whichever you choose, publish the scale before the first assessment and apply it consistently across every student in the section.

Traditional letter grading averages every score across the term, so an early fail can drag a final grade down even after a student demonstrates mastery. Standards-based grading evaluates each learning standard separately on a small ordinal scale (typically 1 to 4) and uses the most recent or most consistent evidence, not the average, to report the final level. The 4-point scale used in this tool follows the common rubric: 4 means the student exceeds the standard, 3 means the student meets it, 2 means partial understanding, and 1 means the standard is not yet evident. SBG works best when paired with clear performance descriptors and an explicit reassessment policy, both of which this tool helps you draft.

A valid scale covers every possible score from 0 to 100 with exactly one band, leaving no gaps and no overlaps. A gap means a score lands outside every band (for example, the band above ends at 79 and the next band starts at 81, so a score of 80 has no grade). An overlap means a single score qualifies for two grades (for example, B is 80 to 90 and A is 90 to 100, so a 90 is ambiguous). This tool flags both errors in real time as you edit the boundaries, so you can fix them before publishing the scale. The convention used here is inclusive lower bound and inclusive upper bound at the top of the scale; intermediate bands meet at integer cut scores with the higher grade winning the tie.

Yes. The output of this tool is a policy table you can paste into your syllabus, share with parents, and use as the scale definition when configuring any gradebook. Most school information systems, including OpenEduCat, let you define a custom grading scale per course or per term with the same fields this tool generates (letter, minimum, maximum, GPA value). Once the scale is defined in the system, raw scores entered against assessments are converted to letter grades automatically and rolled up into report cards and transcripts without any manual conversion. This removes the spreadsheet step and ensures every teacher in a department applies the same scale.

A grade boundary scale defines how raw scores convert to grades across an entire course (for example, 85 percent becomes a B). A rubric defines how to assign a raw score to a single assignment by describing what each performance level looks like on each criterion. You need both. Use the grading-rubric-builder tool to design the rubric you will apply to each assignment, and use this grade boundary maker to define the course-level scale that converts the totals from those rubrics into final grades. Many teachers publish both together in the syllabus, the rubric explains how individual work is judged and the boundary table explains how the term grade is computed.

The lookup field at the bottom of the tool lets you enter any percentage and instantly see which band it falls into using the scale you have just built. This is useful for quick checks while grading (does 84.5 still round up to a B on my scale, or have I set the B cutoff at 85?) and for testing edge cases before you publish the scale. It is also a fast way to answer student questions during conferences without having to scan the table. The lookup uses the same boundary logic as the printed scale, so anything the lookup returns is exactly what your published policy will assign.