Know what's coming before it catches you off guard. Enter your last period and cycle length and we'll map out the next 6 months.
How does the menstrual cycle actually work?
A typical cycle is counted from the first day of one period to the first day of the next. Day 1 is the first day of bleeding. Ovulation typically occurs around Day 14 in a 28-day cycle, but this varies significantly. The fertile window is generally the 5 days before ovulation plus the day of ovulation itself.
Why is my cycle irregular?
Cycles can be affected by stress, significant weight changes, intense exercise, illness, travel across time zones, hormonal birth control starting or stopping, thyroid issues, PCOS, perimenopause, and many other factors. An "irregular" cycle is extremely common and doesn't always indicate a problem — but persistent irregularity is worth discussing with a doctor.
What's a normal cycle length?
Anywhere from 21 to 35 days is considered normal. The "28-day cycle" is an average — most people don't have a perfect 28-day cycle. What matters most is consistency: if your cycle is regularly 32 days, that's your normal.
When am I most fertile?
The fertile window is approximately 6 days long — the 5 days before ovulation and the day of ovulation. Sperm can survive up to 5 days inside the body, so having sex before ovulation can result in pregnancy. An egg only survives 12-24 hours after ovulation.
Can stress delay my period?
Yes — stress affects the hypothalamus, which controls the hormones that regulate your cycle. Significant physical or emotional stress can delay ovulation and therefore delay your period. This is one of the most common reasons for a "late" period that doesn't result in pregnancy.