Terms of Use

Last updated: 2026-04-30

By using HerCalc (hercalc.com), you agree to these Terms. If you do not agree, please do not use the service. These Terms apply to all visitors and users.

1. The service

HerCalc provides free women's health calculators (period, ovulation, due date, BMI, body shape, and others) and educational articles. The service is provided as-is, with no warranty. We may add, change, or remove tools at any time.

2. Not medical advice

HerCalc is for educational and informational purposes only. Nothing on this site constitutes medical advice, diagnosis, or treatment. The calculators are estimators, not diagnostic devices. Your due date, fertile window, BMI category, and any other output is an estimate based on the formula you select and the inputs you provide.

• Always consult a qualified healthcare provider for medical questions.
• Do not delay seeking medical advice because of something you read on HerCalc.
• If you are experiencing a medical emergency, contact emergency services.
• Do not rely on the Safe Period or Ovulation calculator alone for contraception. Calendar-based methods have a typical-use failure rate of about 24% per year.

3. Acceptable use

You agree not to:

• Use HerCalc in a way that violates any law.
• Attempt to disrupt the service, scrape it at abusive rates, or circumvent rate limits.
• Reproduce, distribute, or republish substantial portions of HerCalc content as your own. Quoting with attribution is fine.
• Reverse-engineer, derive source from, or attempt to extract code or data from the service except for what is publicly served.

4. Intellectual property

The HerCalc name, logo, calculators, and original written content are the intellectual property of HerCalc and its contributors. The underlying medical formulas (Naegele's rule, Robinson–Fleming, Hadlock curves, FFIT classification, WHO BMI categories) are public-domain or scientific-literature based and are cited on our Methodology page.

Calculator results and content are licensed for personal, non-commercial use. For commercial licensing, contact hello@hercalc.com.

5. Third-party links

We link to external research papers, professional bodies (ACOG, WHO, ASRM, etc.), and reputable health publications. We do not control external sites and are not responsible for their content or privacy practices.

6. Limitation of liability

To the fullest extent permitted by law, HerCalc and its operators are not liable for any indirect, incidental, consequential, or punitive damages arising from your use of the service, including but not limited to: medical decisions made based on calculator output, fertility planning, contraception failures, or pregnancy-dating disagreements with a clinician.

In jurisdictions that do not allow the exclusion of certain warranties or limitation of liability, our liability is limited to the maximum extent permitted by law.

7. Indemnification

You agree to indemnify HerCalc and its operators against any claims arising from your misuse of the service or violation of these Terms.

8. Changes

We may update these Terms. The "Last updated" date at the top of this page will reflect the most recent change. Continued use of HerCalc after changes constitutes acceptance.

9. Governing law

These Terms are governed by the laws applicable to where HerCalc is operated. Disputes will be resolved in the courts of that jurisdiction unless otherwise required by your local consumer-protection laws.

10. Contact

Questions about these Terms: hello@hercalc.com.