Fertile Days & Ovulation
See this cycle day by day: your period, your fertile days, your peak days and your likely ovulation day, laid out on a calendar.
General information only, not medical advice. Ask your doctor or midwife.
How this works
Formula: Ovulation = cycle length − 14 (cycle day). Fertile days = ovulation day − 5 through ovulation day; peak = ovulation − 2 through ovulation.
- Day 1 of your cycle is the first day of your period.
- Ovulation is estimated at cycle day (cycle length − 14). In a 28-day cycle that is day 14.
- Your fertile days run from 5 days before ovulation to ovulation day. The last 3 of those are your peak days.
- The calendar colours each day so you can see the whole cycle at a glance.
Everything is worked out in your browser. Belly Weekly does not send or store your answers.
Questions
How many fertile days are there in a cycle?
About six: the 5 days before ovulation and the day of ovulation.
Why does my cycle length matter?
The time from ovulation to your next period is fairly steady at about 14 days. The part before ovulation is what changes, so a longer cycle means later ovulation.
Can I get pregnant on my period?
It is less likely but possible, especially with short cycles, because sperm can survive for several days.