AI Math Checker
17 × 24 is 408, not 418, and 15% of 240 is 36. This checker recalculates every "expression = result" it finds in an AI answer and marks the ones that do not match. It checks arithmetic only, not the rest of the answer.
How to use
- Paste an AI answer that contains calculations, such as "12 × 8 = 96" or "15% of 240 is 36". Or press the example button.
- Each calculation found gets a row: Correct, Close or Wrong. Wrong rows are red and show the recalculated value.
- Open the calculator link next to a row to see the working in the Percentage Calculator or the Scientific Calculator.
How it works
The checker scans each line for an expression joined to a result by =, ≈, → or words such as "is" and "equals", and for percent sentences such as "15% of 240 is 36". Expressions use digits, + - × ÷ * / ^ ** and parentheses, with thousands commas, currency signs and % allowed.
Each expression is recalculated with the same hand-written parser as the Scientific Calculator. The text is read as data and never run as code. Precedence is the usual one: parentheses, powers, then multiplication and division, then addition and subtraction. A percent sign divides by 100.
Verdict: Correct when the recalculated value equals the written result, or equals it rounded to the number of decimals written (10 / 3 = 3.33). Close when the difference is under one unit of the last written digit (2 / 3 = 0.66), or the result is marked as approximate and is within 1 percent. Anything else is Wrong. When the exact value has no remainder at the written precision, any different result is Wrong.
"200 + 15% = 230" can mean 200 plus 15% of 200, or 200 + 0.15. Both readings are tried; the row is Correct if either matches, and the other value is shown. A percent sentence "A% of B" is A × B ÷ 100.
FAQ
Can an AI really get arithmetic wrong?
Yes. Language models predict text and do not run a calculator unless a tool is attached, so long multiplications, chains of operations and percentages are common slips. This tool only recalculates; it does not judge the reasoning.
What does it not check?
Word problems without a written expression, equations with variables, units, tables, numbers written as words and European notation such as 1.234,5 are skipped. A Correct row proves that one calculation is right, not the rest of the answer.
Why is a row marked Close?
The written result is one unit of its last digit away from the exact value, as when 2 / 3 is cut to 0.66 instead of rounded to 0.67, or it is marked approximate and within 1 percent. It is worth a look, not necessarily an error.
Where do the calculator links lead?
To the Percentage Calculator and the Scientific Calculator on this site, filled with the same numbers so you can see the working. A link appears only when that calculator exists in your language.
Is my text uploaded?
No. Everything runs in your browser and nothing is sent to a server.