How a calculator is published
- Choose a standard method. Each formula comes from established mathematics and is matched to a named textbook source, listed in our sources.
- Explain it in plain language. Every page gives the formula, the reasoning, worked examples and common mistakes, so you can check a result without having to trust the tool.
- Test it. Before publishing, each calculator is run against answers worked out by hand, including the edge cases listed below.
- Review it. The author, Shaheer Bin Ramzan, reviews every page before it goes live. AI tools are used to help with research and quality checks. They do not replace the review, and the author is responsible for what is published.
- Date it. Each calculator page shows when it was last reviewed.
What we test
- Zero, negative numbers and decimals.
- Empty, invalid and out-of-range input, which should produce a clear message and never a wrong answer.
- Special cases such as no solution, infinitely many solutions, an undefined slope, repeated roots and division by zero.
- Very large numbers, where exact whole-number arithmetic is used.
- Consistency between tools, for example that the distance formula agrees with the Pythagorean theorem.
Known limits
No calculator is perfect, so we state the limits openly.
- Rounding. Results are rounded only at the end, to 12 significant digits. Browsers use double-precision arithmetic, so extremely large or tiny decimals can lose precision.
- Exact tools. The GCF and LCM calculator and the permutation and combination calculator use exact whole-number arithmetic, with stated limits on input size.
- Normal curve. Percentiles from z-scores use a numerical approximation of the normal distribution that is accurate to about five decimal places.
- Quartiles. We use the median-of-halves method. Spreadsheets and other software use other methods and can differ slightly.
- Assumptions. Statements such as the empirical rule assume roughly bell-shaped data, and we say so where they appear.
How often we review
We aim to review every calculator at least once a year, and again whenever a reader reports a problem. Review dates are shown on each page, and changes are recorded in the log below.
Reporting an error
If an answer looks wrong, email contact@onlinemathcalculators.com with the calculator name, the numbers you entered, and what you expected. We read every report, aim to reply within a few days, correct confirmed errors on the page, and record them in the log. If you would like to be credited, tell us.
Using Longhand honestly
These tools are built to help you learn: to check your own working, see a method step by step, and understand why an answer is what it is. Please follow your school’s rules about calculators and outside help in graded work and exams.
Independence
No one pays to influence a calculation, an explanation or a ranking on this site. If advertising is shown, it is kept separate from the content and never changes a result.
Corrections and updates log
| Date | Page | What changed |
|---|---|---|
| November 2026 | All pages | Site launched with 16 calculators, four topic pages, and the About, Author, Accuracy, Privacy, Cookie, Terms and Disclaimer pages. |