Track your menstrual cycle with our free period tracker. Predict your next period, ovulation date, and fertile window to better understand your body's natural rhythm. No Signup Required.
The menstrual cycle is a natural process that occurs in women of reproductive age. Understanding your cycle can help you predict periods, manage symptoms, and track your reproductive health.
| Phase | Duration | What Happens |
|---|---|---|
| Menstrual | Days 1-5 | Shedding of uterine lining, bleeding occurs |
| Follicular | Days 1-13 | Egg follicles develop, estrogen rises |
| Ovulation | Day 14 (approx.) | Release of mature egg from ovary |
| Luteal | Days 15-28 | Progesterone rises, prepares for pregnancy |
*Based on a 28-day cycle. Individual cycles may vary.
| Phase | Common Symptoms |
|---|---|
| Menstrual | Cramping, fatigue, bloating, lower back pain |
| Follicular | Increased energy, improved mood, higher libido |
| Ovulation | Mild pelvic pain, increased discharge, slight temperature rise |
| Luteal | PMS, breast tenderness, mood changes, food cravings |
| Hormone | Menstrual Phase | Follicular Phase | Ovulation | Luteal Phase |
|---|---|---|---|---|
| Estrogen | Low | Rising | Peak | Moderate, then falls |
| Progesterone | Low | Low | Begins to rise | High, then falls |
| FSH | Low | Rising | Low | Low |
| LH | Low | Low | Surge | Low |
FSH = Follicle Stimulating Hormone, LH = Luteinizing Hormone
Menstrual tracking has ancient roots dating back to 5th century BCE, when Greek physician Hippocrates first documented cycle patterns. The earliest physical period trackers were beaded necklaces used by indigenous women, with different colored beads marking cycle phases. Modern digital tracking began in the 1990s, but exploded with smartphone apps in 2010. Interestingly, NASA initially banned female astronauts from space missions partly due to menstruation concerns, until research proved cycles function normally in zero gravity. Studies show that tracking improves cycle awareness by 64% and helps identify health conditions like endometriosis 2-3 years earlier than otherwise. Globally, over 200 million women now use digital period trackers, generating data that has revolutionized reproductive health research.
Modern period tracking algorithms employ more than simple calendar counting. Advanced trackers use Bayesian statistical models that continuously refine predictions based on user-reported data. These models calculate probability distributions rather than fixed dates, accounting for natural cycle variability. The most sophisticated systems incorporate symptom correlation analysis, identifying patterns between cycle phases and reported symptoms like mood changes or physical discomfort. Browser-based trackers face unique challenges in data persistence, typically using localStorage or IndexedDB to maintain records without server storage. Computational efficiency is critical—the best implementations use memoization techniques to cache previous calculations, reducing processing needs by up to 70% compared to recalculating each time, while maintaining prediction accuracy within a 1-2 day margin for regular cycles.
A period tracker is a tool that helps track and predict your menstrual cycle. By entering the start date of your last period and your average cycle length, you can estimate when your next period will begin, when you're ovulating, and identify your fertile window.
This tracker provides estimates based on average cycle data. While it's generally reliable for those with regular cycles, individual cycles can vary due to stress, illness, medication, or other factors. For the most accurate tracking, consider using this tool alongside other fertility awareness methods.
The fertile window is the period during your menstrual cycle when pregnancy is most likely to occur. It typically includes the 5 days before ovulation plus the day of ovulation itself. Sperm can survive in the female reproductive tract for up to 5 days, while an egg is viable for about 24 hours after ovulation.
Our tracker identifies your current cycle phase based on today's date and your inputs. The menstrual cycle has four main phases: the menstrual phase (when bleeding occurs), the follicular phase (when follicles develop), ovulation (when an egg is released), and the luteal phase (after ovulation until your next period).
While this tracker works best for those with regular cycles, you can still use it with irregular periods by entering your average cycle length. However, the predictions may be less accurate. If your periods are consistently irregular, we recommend consulting with a healthcare provider.
Yes, we take data security seriously. All calculations are processed locally in your browser and never sent to our servers. This ensures complete privacy and security of your personal health information.
While this tracker can help identify your fertile window, it should not be used as the sole method of contraception or conception planning. For family planning purposes, please consult with a healthcare provider for personalized advice.