Your Information
Usually 21-35 days, with 28 being average.
Fertility Window
Please pick a date and enter your cycle length to view your fertility window.
Calculate your most fertile days based on your last period and cycle length. Perfect for planning pregnancy.
Please pick a date and enter your cycle length to view your fertility window.
A Fertility Calculator is a digital tool designed to help individuals or couples track the most fertile days within a woman’s menstrual cycle. It estimates the “fertile window”—the days when conception is most likely to occur—based on information such as the start date of the last period and the average cycle length.
The primary goal of a fertility calculator is to pinpoint ovulation, the moment an egg is released from the ovary. Since the egg survives only 12–24 hours, timing is crucial. The calculator estimates when ovulation will happen, helping users maximize their chances of getting pregnant.
Using our Fertility Calculator empowers users with insights to make informed reproductive health decisions.
Understanding how fertility works is the key to using any fertility tracking tool effectively.
Ovulation is the process where a mature egg is released from the ovary. This typically occurs about 14 days before the start of the next period.
The fertile window includes:
That gives you a 6–7 day window each cycle when you’re most likely to conceive.
Using our personalized tool is simple, fast, and private. It’s designed to give you accurate ovulation predictions and fertility windows based on your unique cycle.
Each menstrual cycle has four phases, each playing a critical role in fertility.
In a 28-day cycle, ovulation usually occurs on Day 14. But not all women are the same, so it’s essential to calculate based on your personal cycle length.
Our calculator customizes ovulation predictions using your actual data, not generic averages.
The fertile window typically spans 6 days:
The two days before ovulation and ovulation day are the most fertile. Intercourse during this window gives the highest probability of pregnancy.
These signs, combined with our calculator, increase prediction accuracy.
Timing intercourse correctly can boost conception chances by over 30%. Our tool helps you make the most of your cycle.
Understanding your cycle brings confidence and control, especially for those struggling with irregularity.
For those avoiding hormonal contraceptives, this is a natural and side-effect-free method of family planning.
Our calculator uses proven biological data and ovulation trends, then adapts it to your cycle.
In these cases, manual tracking or consultation with a healthcare provider may help.
If your cycle varies greatly each month, results may fluctuate. It’s still helpful for tracking patterns over time.
Conditions like PCOS, thyroid disorders, or endometriosis can disrupt ovulation and affect calculator accuracy.
High stress, travel, poor sleep, and diet can all affect cycle regularity.