By guzg · October 6, 2026 · 6 min read

I put the conversion charts published by several GPA calculator sites side by side, expecting them to be minor variations on the same thing. They aren't. Run a single grade through three of the charts in circulation and you get three different GPAs.

The grade I used to test this was 85%. Here is what came back.

Three charts, three answers for 85%

Two of the three agree, which is reassuring until you notice the third one differs by 0.7 points on a single course. Apply that across a transcript and the gap is the difference between a 3.2 and a 3.7 cumulative.

And 85% isn't a special case. Try 90%:

Same pattern: two charts agree, one disagrees, and the disagreement can move your GPA by a third of a point per course.

Why they diverge

Two independent decisions produce all the variation.

Decision one: where does an A start? The standard US scale with plus and minus grades puts an A at 93%. The simpler ten-point scale puts it at 90%. That single choice shifts everything above 90% by a third of a point.

Decision two: do plus and minus grades exist? If they do, 85% is a B (3.0) and 90% is an A− (3.7). If they don't, both are simply B and A. This sounds like a small detail, but it means the same percentage can land on a 3.0 or a 3.3 depending on whether the chart distinguishes B from B+.

Put those two decisions together and you get several defensible charts, each internally consistent, each producing different numbers from the same transcript.

The international variant deserves a note

The third chart is the one that surprised me most, because it produces systematically higher numbers than the US scales.

The reason for the difference isn't sloppiness. These charts are usually built for students converting a percentage-based transcript from a system with a 60% pass mark, where a 75% genuinely is a solid result. The US standard scale assumes a different distribution entirely, where 75% is barely above a C.

So neither table is wrong. They were built for different inputs.

How to tell which one you should use

There's no universal answer, but you can narrow it down with two questions:

1. Does your school award plus and minus grades? If it does, use a chart that has them. If a plain B is the only option, use a chart without them.
2. What is your school's pass mark? If it's 60%, you want a chart that maps 60% to roughly a 1.0. If it's 40%, you need one that maps 40% to a 1.0, and the number will come out higher.

If you can answer both, the correct chart usually picks itself, and the other two become irrelevant rather than confusing.

What to do when you genuinely don't know

If a form demands a number and you have no idea which chart applies, my honest suggestion is this: pick the chart that matches your school's pass mark and whether it uses plus/minus grades, state the figure, and mention the original system somewhere in your application.

What you shouldn't do is average the charts, or pick the highest one because it looks better. Admissions readers who work with international transcripts will recognise an inflated conversion, and it's a worse signal than a modest number that's honestly derived.

A note on method

I compared published conversion charts rather than running each site's calculator with a sample transcript. That means I'm comparing what they say they do, not necessarily what their code produces on every input. The disagreement between the charts is real and reproducible by hand; whether any particular site's calculator matches its own published chart is a separate question I can't answer from the outside.

If you want to see the arithmetic for a specific system, the GPA calculator lets you pick the source scale explicitly and shows the pass line it assumed, so at least you know which chart you're working from.