Effective date: 22 October 2026
1. Scope and definitions
These terms govern your use of the calculators and guides on calctool.cc (Dimensionless Number Calculator, “the site”), a personal project run by one individual. By using the site you agree to these terms. The handling of personal information is covered by the privacy policy.
- “Operator” means the individual who builds and maintains the site.
- “User” means anyone who visits the site to use a calculator or read a guide. There are no accounts, so there is no sign-up.
- “Content” means the site’s calculators, basic guides, calculation notes, tables, examples and their explanations.
2. What the site provides, changes and suspension
The site provides dimensionless-number calculators, guides and calculation notes free of charge. The operator may modify, add or remove content to fix errors or improve it; changes to formulas and examples are recorded in the public repository’s commit history. Part or all of the site may be suspended because of hosting outages, maintenance or the operator’s circumstances, and because the service is free, no compensation is offered for suspension.
3. No warranty for results
- The calculators only substitute your inputs into a formula. They do not check whether your inputs are correct or whether the formula suits your problem. If you enter a diameter in millimetres, for example, the calculator treats the number as metres.
- The operator does not warrant the accuracy, completeness, currency or fitness for a particular purpose of any result or guide.
- Regime labels such as laminar or turbulent and the explanatory sentences shown with results are general guidance based on boundary values for representative cases, not determinations for your conditions.
- Do not rely on the site alone for design, construction, safety, regulatory compliance, experiment planning or any other decision where results matter; confirm with original data and qualified review.
- Property values in the examples come from the documents and conditions listed in the references, and operating conditions such as pipe diameter or velocity are assumptions stated in each example. Neither replaces your actual conditions.
4. Your responsibility to check, and limitation of liability
Before using a result, check that the units of your inputs, the temperature and pressure conditions of your property values and the definition of the characteristic length match your problem. To the extent permitted by applicable law, the operator is not liable for direct or indirect loss arising from using, or being unable to use, the site’s results or guides, including loss caused by interruptions, errors or delays. This does not apply to loss caused by the operator’s intent or gross negligence.
5. External links and advertising
The site links to external websites as sources and shows Google AdSense ads. The operators of external sites are responsible for their content, accuracy and privacy practices, and links may change or disappear. Advertisers are responsible for their ads and the products or services advertised; the operator does not endorse them.
6. Rights
Rights in the site’s text, tables, figures and code belong to the operator or their respective owners. To copy or redistribute beyond what the law allows as quotation, ask first through GitHub Issues.
7. Prohibited conduct
The following are prohibited:
- disrupting the site with excessive automated requests in a short time;
- altering the site’s code or ads to show to other users;
- presenting the site as being run by someone other than its operator, or presenting its results as values guaranteed by the operator;
- clicking ads fraudulently or encouraging others to click them.
8. Changes to these terms
The operator may change these terms when needed. Changed terms will be posted on this page with a new effective date, and significant changes that disadvantage users will be announced on this page before they take effect. Earlier versions are available in the repository history. These terms replace the English terms published in January 2026.
9. Severability
If any provision of these terms is invalid or unenforceable under applicable law, the remaining provisions continue to apply.
10. Contact
Questions about these terms are received through GitHub Issues. It is a public board, so do not include personal information. The Korean version at /terms prevails if the two differ.