Period Calculator
Predict your next period date and expected cycle timing in seconds.
Try it free
About Period Calculator
Free, Accurate & Medically Reviewed Menstrual Health Tools for Everyone
We believe every person deserves free access to accurate menstrual health information. Our tools and guides are built to be practical, medically reviewed, and respectful of your privacy.
- Free Tools
- 0
- Medical Reviewer
- 0
- Sign-up Required
- 0
- Founded
- 0
Who We Are
Who We Are
Period Calculator is a free online menstrual health resource dedicated to making accurate, science-based reproductive health information accessible to everyone without paywalls, without sign-ups, and without judgment.
We are a team of health content specialists and developers who believe that understanding your body should not require a medical degree or an expensive app subscription. Whether you are tracking your cycle for the first time or navigating irregular periods and fertility planning, this site is built to help.
Our tools are used by people who are:
- Trying to conceive and looking for their fertile window.
- Tracking cycles for general health awareness.
- Managing irregular periods or hormonal conditions.
- Planning around their cycle for daily life.
Every calculator, every article, and every piece of health content on Period Calculator is reviewed by a board-certified OB-GYN before publication because menstrual health decisions deserve accurate information.
What We Offer
Free tools and guides, no account required
Period Calculator combines fast calculators with medically reviewed health education so visitors can move from a quick estimate to a clearer understanding of what the result means.
Ovulation Calculator
Find your fertile window and best days to try to conceive.
Try it freePeriod Tracker
Log and visualize your cycle history with local-first tracking.
Try it freeSafe Period Calculator
Understand lower-fertility and higher-fertility days across your cycle.
Try it freePregnancy Calculator
Track due date timing and milestone planning from key pregnancy dates.
Try it freeHealth Blog
Read medically reviewed guides on periods, ovulation, fertility, and hormonal health.
Read guides
Medical Review Standards
Our Medical Review Standards
At Period Calculator, we take medical accuracy seriously. Menstrual health directly affects daily life, fertility decisions, and overall wellbeing, so the information we publish has to be trustworthy, current, and clinically sound.
We distinguish clearly between educational health content and personal medical advice. Our goal is to explain cycle health, fertility timing, and calculator logic responsibly while encouraging readers to seek individual care from a qualified clinician when needed.
- All health-related articles and tool explanations are reviewed by Dr. Sarah Mitchell, MD, before publication.
- Editorial standards are aligned with current ACOG, ASRM, and WHO reproductive health guidance.
- Statistical claims are checked against peer-reviewed sources such as NEJM, Human Reproduction, Fertility and Sterility, and BMJ.
- Articles are updated when clinical guidance or meaningful evidence changes.
- We clearly distinguish educational content from personal medical advice and recommend consulting a healthcare professional for individual care decisions.
- Articles discussing specific conditions include a visible medical disclaimer and a last reviewed date.
Medical Reviewer
Meet Our Medical Reviewer
Dr. Sarah Mitchell, MD
OB-GYN, Board Certified
15+ Years Clinical Experience
Dr. Sarah Mitchell is a board-certified obstetrician and gynecologist with over 15 years of clinical experience specializing in reproductive endocrinology, menstrual disorders, fertility awareness, and hormonal health. She reviews health content published on Period Calculator for clinical accuracy, context, and alignment with current ACOG and ASRM guidance.
Specializations
- •Reproductive Endocrinology
- •Menstrual Disorders (PCOS, Endometriosis)
- •Fertility Awareness & Natural Family Planning
- •Perimenopause & Hormonal Health
Editorial Process
Our Editorial Process
We follow a four-step workflow for every article and explanation published on Period Calculator. That process keeps the site transparent, medically cautious, and editorially independent.
- 1
Step 1
Research & Writing
Our health content team starts with peer-reviewed medical literature, clinical practice guidelines, and authoritative health organization resources. Every factual claim is identified and sourced before writing begins.
- 2
Step 2
Medical Review
Before any health content is published, it is reviewed by Dr. Sarah Mitchell, OB-GYN, for clinical accuracy, appropriate context, and alignment with current ACOG and ASRM guidance.
- 3
Step 3
Fact-Checking & Source Verification
All statistics, study citations, and medical claims are independently verified against original source materials. References are listed so readers can review the evidence directly.
- 4
Step 4
Publication & Ongoing Updates
Medical knowledge evolves. We monitor new research and updated guidance, and we revise our content when meaningful evidence changes. Every article displays its publication and review dates.
Our Commitment
We are committed to providing content that is accurate, balanced, and free from commercial bias. We do not accept payment to feature specific products, treatments, or medical opinions. Editorial decisions are made independently of monetization or partnership pressure.
Contact Us
We'd love to hear from you
We welcome questions, feedback, correction requests, and collaboration inquiries from readers, healthcare professionals, and partners.
Contact Information
Have a question, suggestion, or feedback? We review messages in the order received. Include the relevant page, tool, or article in your message so we can check the right context faster.
What You Can Contact Us About
- Questions about how our calculators work.
- Feedback on tools, articles, or design.
- Medical accuracy concerns or correction requests.
- Partnership and collaboration inquiries.
- Press, media, and general business inquiries.
Medical questions: Period Calculator is an educational health resource, not a medical provider. For personal medical advice, please consult a qualified healthcare professional.
Send Us a Message
Fields marked with an asterisk (*) are required. On this static site, submitting the form opens a prefilled email draft in your default mail app.
This form does not send data to a hidden on-site inbox. You review the draft in your own email application before anything is sent.
Legal & Policies
Legal & Policies
Transparency matters. Review our privacy, terms, and cookie policies for details on how Period Calculator operates and how we handle user data and site preferences.
Privacy Policy
Learn how we handle local browser data, contact form submissions, and privacy choices.
ReadTerms of Service
Read the rules and important limitations that apply when you use Period Calculator.
ReadCookie Policy
Review the cookies section inside our Privacy Policy for browser storage and privacy choices.
ReadMedical Disclaimer
Period Calculator provides educational health information only. Our content is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider for personal medical decisions.
Medical Disclaimer: Content on this site is for educational purposes only and does not constitute medical advice, diagnosis, or treatment. Calculators and health guides are planning aids based on general menstrual health patterns and may not reflect individual variation. Always consult a qualified healthcare professional for personal medical decisions. Last reviewed by Dr. Sarah Mitchell, MD on March 17, 2026.