These Terms of Service ("Terms") govern your use of periodcalculator.wiki and the Period Calculator tool. By visiting the site or using the calculator, you agree to these Terms. If you do not agree, do not use the site.
1. Service description
Period Calculator provides a browser-based calculator and general educational content for estimating upcoming menstrual-cycle dates. The tool can use the first day of a last period, an average cycle length, an optional period length, and optional shortest and longest cycle values to display calendar estimates.
The site may change, improve, pause, or remove features. Basic calculations are designed to run locally in the browser, but availability can depend on your device, browser, network, hosting, analytics, security, and third-party services.
2. General health disclaimer
The calculator is for general education and planning. It is not medical advice, a diagnosis, a pregnancy test, a fertility assessment, an ovulation test, or a substitute for care from a qualified healthcare professional. Calendar estimates cannot confirm ovulation, explain a late period, or determine whether a symptom is safe to ignore.
Do not use Period Calculator as contraception or to decide whether unprotected sex is safe. Contact a qualified healthcare professional for concerns about pregnancy, repeated major cycle changes, severe pain, unusually heavy bleeding, or other symptoms. Seek urgent care for an emergency.
3. Your inputs and responsibility
You are responsible for entering dates and cycle values carefully and for interpreting the result as an estimate. A wrong start date, an unrepresentative average, or a large change in cycle timing can make the output less useful. You should update the calculator with an actual start date when a new cycle begins if you continue using the calendar.
You are also responsible for keeping your device, browser, and email account secure. Do not enter information that you do not want displayed on your device or processed by browser, analytics, advertising, or support systems.
4. Acceptable use
- Do not attempt to disrupt, overload, attack, or interfere with the site.
- Do not use the site to violate applicable law or another person’s rights.
- Do not scrape the site aggressively, bypass security controls, inject malicious code, or test vulnerabilities without authorization.
- Do not misrepresent Period Calculator as a healthcare provider or claim that its estimates are clinically confirmed.
- Do not use the site to create deceptive, harmful, or unlawful health claims.
5. Accuracy and availability
We aim to make the formulas, examples, labels, and limitations clear, but we do not guarantee that every estimate will match an individual cycle or that the site will remain error-free and available at all times. Browser date behavior, time zones, daylight-saving changes, extensions, content blockers, and third-party services can affect how a page appears.
You should independently review important health decisions with an appropriate professional. You should also keep your own records if you need a dependable personal history; the basic calculator is not a storage or reminder service.
6. Intellectual property
The Period Calculator name, original site text, layout, organization, interface, and branding are owned by the site operator or used with permission unless otherwise stated. You may not copy the site in a way that suggests a false relationship, endorsement, or clinical affiliation.
You may use the calculator output for your own general planning, subject to these Terms and the health limitations above.
7. External links
The site may link to external health resources, policies, documentation, analytics providers, or other websites. We do not control third-party content, availability, privacy practices, or terms. A link is provided for context and does not mean that every statement or service on the linked page is endorsed.
8. Disclaimers and limitation of liability
The site and calculator are provided on an "as is" and "as available" basis to the maximum extent permitted by law. We do not warrant that the tool will meet every need, produce a specific health outcome, remain available, or be free of errors or interruptions.
To the maximum extent permitted by law, Period Calculator and its operators are not liable for indirect, incidental, consequential, special, exemplary, or punitive damages arising from your use of the site, inability to use the site, interpretation of an estimate, support communication, or reliance on external content. Some jurisdictions do not allow every limitation, so parts of this section may not apply to you.
9. Changes to these Terms
We may update these Terms when the calculator, site features, support process, or legal requirements change. We will update the effective date when material changes are published. Continued use of the site after an update means the revised Terms apply to future use.
10. Contact
Email: [email protected]
Website: periodcalculator.wiki