How we calculate

GpaAndPercentage is a free set of calculators for grades and everyday math. We built it because most calculators give you a number with no explanation, and a number you cannot check is not much use when a grade or a decision depends on it.

What makes these tools different

• The working is always shown. Every result comes with the formula and the steps, the way a teacher would want to see it.
• Assumptions are stated. GPA scales, rounding rules and sample-versus-population choices vary. Each page says which one it uses and how to switch.
• Privacy by default. Calculations run in your browser. We measure which tools are used so we can improve them, but we never receive the numbers you type.

How we check our tools

Before a calculator is published, it is tested against a set of known answers (including edge cases such as zero, negative numbers, empty fields and very large values). The formula and worked example on each page are checked by hand. When a tool changes, the tests run again. If you find a wrong answer, please tell us; corrections are made within a few days and noted on the page.

Grading scales

GPA tools use the common US 4.0 scale (A = 4.0, B = 3.0 and so on, with plus and minus grades). Many schools use different scales or weightings. Where your school publishes its own scale, that scale is always the one that counts.