For Catholic women and married couples
Understand your body. Honor God’s design.
Your body has a natural rhythm, and learning to understand it should not require complicated predictions, endless data, or an app telling you what your body is supposed to do.
Corvia is a Catholic cycle charting app built around the Billings Ovulation Method. It gives you a simple, thoughtful place to observe your cycle, record what you notice, and begin recognizing the patterns your body reveals over time. With prayer, learning, and optional sharing woven into the experience, Corvia brings together the practical and spiritual sides of understanding your fertility.
Whether you are learning about your cycle for the first time or practicing Natural Family Planning within marriage, Corvia helps you grow in understanding without taking the interpretation out of your hands.
30 days free. Then $59.99/year or $8.99/month. Cancel anytime.
Prediction or observation
Most women are familiar with period apps that ask when their last period started, calculate an estimated cycle length, and predict when their next period or ovulation might occur. These tools can be useful for general calendar planning, but a prediction is not the same as observing what is happening in your body.
The Billings Ovulation Method takes a different approach. Rather than relying on an expected schedule, it teaches you to recognize changes in sensation and cervical mucus throughout your cycle. These natural signs help you learn your individual fertility pattern, even when your cycles do not follow a predictable calendar.
A period app
Asks when your last period started, calculates an estimated cycle length, and predicts when your next period or ovulation might occur.
Predicted from past cycles.The Billings Method
Teaches you to recognize changes in sensation and cervical mucus throughout your cycle, even when your cycles do not follow a predictable calendar.
Observed in the current cycle.Corvia was designed around that philosophy. Instead of giving you an algorithm’s interpretation of your fertility, it provides a place to record your own observations and see how your pattern develops. You remain responsible for understanding what those signs mean, with guidance from a qualified Billings instructor when needed.
For Catholic women and married couples, this approach reflects something meaningful about the body. Fertility is not simply a number to calculate or a problem to solve. It is part of the way we were created, and learning to understand it can become an act of attention, gratitude, and responsibility.
The method
At the heart of Corvia is a simple principle: your body gives you information every day, and your observations matter more than a predicted date on a calendar.
The Billings Ovulation Method teaches women to recognize changes in sensation at the vulva and the appearance of any discharge. These observations are made naturally throughout the day and recorded in the evening, creating a picture of how the cycle changes over time.
Corvia follows that same practice. You record the sensations you actually experience, and the app organizes them into a color-coded Billings chart. Rather than assuming every woman’s baseline looks the same, Corvia allows you to identify your usual pattern, whether that means dryness, an unchanging discharge, or a pattern you are still learning to recognize.
The app also respects the retrospective nature of Peak Day. In the Billings Method, Peak is identified by looking back at the final day of slippery sensation after a change has occurred. Corvia allows you to confirm that observation yourself rather than automatically assigning a Peak Day.
And if you miss a day, the chart reflects that no observation was recorded. Corvia does not invent information or fill in the gaps with assumptions.
This distinction is important. Corvia does not predict ovulation, determine whether you are fertile or infertile, or tell you when to have intercourse. It gives you a clear record of what you observed so you can learn to interpret your cycle through the Billings Method.
Your understanding grows through observation and education, not an algorithm making decisions for you.
Pray. Observe. Chart. Learn.
Understanding your cycle does not need to become another complicated task in your day. Corvia brings four parts of the experience together, allowing you to build a consistent practice in a way that fits naturally into your life.
Begin with a moment of prayer, today’s Scripture, or time with the Rosary. Corvia includes Catholic prayers, saints by intention, and feast days throughout the year, giving you a quiet place to return to your faith whenever you need it.
Prayer is there to accompany your day, not to measure your progress or add another obligation.
As you move through your day, pay attention to the sensations you naturally experience at the vulva. The Billings Method does not require internal examinations, temperatures, or hormone monitors.
Corvia uses simple, familiar language to help you describe what you noticed. You can also record the appearance of any discharge, along with additional details you find meaningful.
At the end of the day, take a moment to record your observation. Corvia places it into your color-coded Billings chart, creating a visual record of your cycle as the days unfold.
You can also include optional notes about mood, energy, or anything else you want to remember. Over time, those daily observations become a record you can reflect on and share with your instructor when guidance is needed.
Corvia includes guided education to help you understand the method behind your observations. Its nineteen short lessons introduce the principles of Billings, explain what to notice, and help you become more familiar with the patterns appearing on your chart.
The same Billings 101 course is also available completely free on our website, with no account required. We believe understanding your own body should begin with education, whether or not you choose to use Corvia.
Built for Billings
There is a difference between an app that offers a place to record cervical mucus and one thoughtfully designed around the Billings Ovulation Method.
Corvia was built specifically for women learning and practicing Billings. Its daily observations, charting language, color system, and approach to Peak Day reflect the principles of the method rather than adapting a general period-prediction system.
The experience begins by helping you become familiar with your usual observations. As your chart develops, Corvia gives you a place to distinguish between an established pattern and changes that may be significant within the method. It also preserves the observations surrounding Peak Day so you and your instructor can review how the pattern unfolded.
This approach matters because the Billings Method is not simply a collection of individual symptoms. It is a way of understanding changing patterns, and those patterns need to be considered in the context of the woman’s own cycle.
Corvia is designed to support that practice through different seasons of reproductive life, including postpartum, breastfeeding, irregular cycles, and perimenopause. These seasons can require additional instruction, particularly when a couple is postponing pregnancy, but they do not require a woman to fit her observations into a predetermined calendar.
The method teaches you how to understand your fertility. Corvia gives you a place to record that understanding.
Faith
There are plenty of ways to record a menstrual cycle. What we wanted to create was something different: a space where understanding your body and living your Catholic faith did not feel like two unrelated parts of your life.
Corvia includes a dedicated prayer library with daily Scripture, the Rosary, prayers for different intentions, and a growing collection of saints. You can explore saints by the intentions closest to your heart, choose those you feel particularly connected to, and see their feast days appear throughout the calendar.
These spiritual elements are not connected to your fertility status. Corvia does not assign prayers according to where you are in your cycle or suggest that a particular biological change has a spiritual meaning. Prayer remains something freely entered into, whatever season of life you are experiencing.
For married couples, this connection can become especially meaningful. Natural Family Planning involves more than learning fertile and infertile times. It also involves conversations about children, responsibilities, intimacy, sacrifice, and the life you are building together.
Catholic teaching calls spouses to approach these decisions with generosity toward life and responsible discernment. Corvia cannot make those decisions for you, but it can provide space for your observations and your prayer life to exist within the same daily experience.
Your body and your faith were never meant to be separate conversations.
Read Why We Built a Prayer Tab Into a Cycle App →Sharing
Learning your cycle is a personal experience, but that does not mean you have to navigate every part of it alone.
For married couples, Natural Family Planning involves both husband and wife. Although the daily observations happen in her body, the conversations and decisions surrounding fertility belong to both spouses.
Your husband
Corvia offers optional read-only sharing so your husband can see the chart you choose to share. He can become more familiar with your cycle and participate in conversations with a clearer understanding of what you are observing, without needing to interpret the chart on your behalf or change your observations.
Your instructor
For women learning from a qualified Billings instructor, Corvia also makes it possible to share a chart for review. Your instructor can see the recorded observations and help you recognize patterns, understand the method’s guidelines, and work through questions specific to your circumstances.
You decide when to share, and sharing does not give someone permission to edit your chart. For married women who choose to record intercourse, that information is optional and handled through separate sharing choices.
The goal is not to give everyone access to your cycle. It is to make meaningful support available when you choose to invite someone into the experience.
Privacy
Fertility observations can be deeply personal, especially when they include the intimate details of married life. We believe that information deserves to be treated with care and respect.
Corvia was designed with privacy as a core commitment, not an optional feature. Your observations belong to you, and sharing your chart is always a choice. Optional intercourse information is handled separately, with additional controls over what you choose to include.
We do not sell your personal cycle data to advertisers, insurance companies, or other third parties. Corvia also provides account deletion controls so you can choose to leave the platform and request removal of your information in accordance with our policies.
The purpose of Corvia is to help you understand your body, not to turn the most personal parts of your life into someone else’s business.
Read Our Privacy and Intended-Use Information →Starting points
You do not have to be married, planning a family, or even familiar with Natural Family Planning to begin learning about your cycle.
Corvia was created to meet women in different seasons of life, with an experience shaped around what is appropriate and meaningful for each one.
For a young woman just beginning to understand her cycle, Corvia offers a gentle introduction to menstruation, body changes, and the natural signs of fertility.
The experience focuses on education, simple observations, and prayer, without intercourse recording or adult relationship content. It is designed to help young women approach their changing bodies with understanding and respect rather than confusion or embarrassment.
Explore Beginning Womanhood →For a woman who wants to know her body better, Corvia offers a way to practice the Billings Method without placing family planning at the center of the experience.
You can observe your cycle, build your chart, explore the lessons, and recognize patterns that become familiar over time. Whether you are single, discerning marriage, or simply curious about your reproductive health, the focus remains on understanding the body you have been given.
Explore Understanding My Cycle →For married Catholic couples, Corvia brings Billings charting together with prayer, shared understanding, and the practical experience of Natural Family Planning.
You can record daily observations, share your chart with your husband or instructor, and choose whether to include intercourse information. The experience also makes room for the intentions and conversations that come with responsible parenthood, whether you are hoping to welcome another child or prayerfully discerning a reason to postpone pregnancy.
Explore Corvia for Marriage →One app, with an experience shaped around your season of life. You can change your starting point as your circumstances change, without losing the observations you have already recorded.
Anywhere
Corvia is available through your web browser, whether you are using a phone, tablet, or computer. You do not need to purchase a fertility monitor or install specialized equipment to begin.
On supported phones, Corvia can also be added to your home screen for convenient access, with a daily reminder to help you establish your evening charting routine.
Your observations remain part of the same account, so you can return to your chart from another device whenever you need to.
Native iPhone and Android apps are planned for the future. In the meantime, the web experience is available now.
Pricing
We wanted Corvia to feel accessible, without complicated subscription levels or additional purchases to unlock the parts of the experience that matter.
Your subscription includes daily Billings charting, guided lessons, the Catholic prayer library, and optional spouse and instructor sharing.
Your first thirty days are free, giving you time to explore the app, begin making observations, and become familiar with the experience before your subscription begins.
Best value
Annual
$5.00/mo
$59.99 billed annually
Flexible
Monthly
$8.99/mo
Billed month to month
There are no separate feature tiers. You choose the billing option that works for you, and you can cancel from your profile whenever you choose.
A payment method is required when you begin your trial, but you will not be charged during the first thirty days. If you cancel before the trial ends, no subscription payment is collected.
Every feature included. Cancel anytime.
Common questions
Corvia is an independent Catholic cycle charting app built around the Billings Ovulation Method. It is not currently certified or endorsed by WOOMB International or BOMA-USA. We encourage women practicing Billings for Natural Family Planning to learn from a qualified instructor and use Corvia as a tool to support that learning.
No. Corvia records your observations and displays them in a Billings chart, but it does not determine your fertility status, predict ovulation, or recommend when to have intercourse. Interpreting your chart requires understanding the method and applying its guidance to your circumstances.
You can begin exploring Corvia and learning about the Billings Method without an instructor. However, if you plan to use Billings for family planning, especially when postponing pregnancy, learning with a qualified instructor is strongly encouraged. Corvia offers optional chart sharing to support that relationship.
Yes. The Billings Ovulation Method can be learned and practiced by women of any faith. Corvia is intentionally Catholic in its design and includes Catholic prayers, saints, Scripture, and the liturgical calendar, but you can use its cycle observation and charting features regardless of your religious background.
No. Corvia is designed around the Billings Ovulation Method, which relies on observing sensation at the vulva and the appearance of any discharge. You do not need a basal thermometer, hormone testing strips, or a wearable device to practice the method.
Yes. The Billings Method is based on observing current fertility signs rather than predicting ovulation from previous cycle lengths, and it can be taught during postpartum, breastfeeding, perimenopause, and irregular cycles. These circumstances may require additional guidance, so working with a qualified instructor is particularly important.
Yes, but only when you choose to share it. Corvia offers optional read-only access for your husband, allowing him to see the chart without changing your observations. You remain in control of sharing, and intercourse recording is optional within the Married experience.
Corvia includes a Beginning Womanhood experience designed for younger women learning about menstruation and the changes happening in their bodies. It focuses on education, simple daily observations, and age-appropriate Catholic content without intercourse recording or adult relationship features.
Corvia currently runs through a web browser and can be accessed on phones, tablets, and computers. On supported phones, you can add it to your home screen for convenient access. Native iOS and Android applications are planned but are not currently available in the app stores.
At the end of your thirty-day trial, your selected subscription begins at $59.99 annually or $8.99 monthly. You can cancel from your profile before your trial ends without being charged, and your observations remain available if you continue with a paid subscription.
Your cycle is already telling a story. You do not need an algorithm to write it for you, and you do not need to understand everything on the first day.
Corvia gives you a simple place to begin, with the Billings Method at its foundation and your Catholic faith woven naturally into the experience.
Understand your body. Honor God’s design. Begin with Corvia.
30 days free. Cancel anytime.