What is a menstrual cycle calendar tool? A menstrual cycle calendar tool is a digital resource that overlays your cycle phases onto a calendar you already use — like Google Calendar or Apple Calendar — so you can plan your work, rest, and daily life around your natural hormonal rhythms. Rather than just tracking when your period is due, a menstrual cycle calendar tool shows you all four phases of your cycle: menstrual, follicular, ovulatory, and luteal. Nadi is a menstrual cycle calendar tool built for women who want to plan with more awareness and less self-judgment.

Is Nadi an app I need to download? No. Nadi's menstrual cycle calendar tool overlays onto the calendar you already use — Google Calendar or Apple Calendar. There is nothing new to download. Nadi's education, support, and community are delivered through newsletters and events, so nothing requires an app.

How is Nadi different from period tracking apps like Flo or Clue? Period tracking apps typically focus on predicting when your next period will arrive. Nadi's menstrual cycle calendar tool is designed for planning and awareness across all four cycle phases — not just menstruation. The focus is on understanding what each phase might mean for your energy, focus, mood, and capacity, and using that understanding to plan your work and life more realistically. Nadi also integrates directly with the calendar you already use, rather than requiring a separate app.

I already track my period. How is Nadi different? Period tracking tells you the dates you will bleed. Nadi's menstrual cycle calendar tool helps you understand all four phases of your cycle — menstrual, follicular, ovulatory, and luteal — and what those phases might mean for your energy, focus, and capacity. The goal is not just to know when your period is coming, but to understand your whole-cycle patterns so you can plan more effectively across the month.

Is Nadi the same as cycle syncing? Not exactly. Cycle syncing is a term used to describe aligning activities with your cycle phases. Nadi draws on those principles, but we are not about rigid rules or prescriptive schedules. We are about understanding your individual patterns so you can make better decisions about how to plan your time, with more awareness and less self-criticism. Every woman's experience of her cycle is different, and Nadi reflects that.

Who is Nadi for? Nadi is for women who want to understand how their menstrual cycle affects their energy, focus, and mood — and use that understanding to plan their work and personal life more effectively. This includes women in employed and self-employed roles, those working demanding schedules, and workplaces that want to support their female employees with menstrual health awareness tools and education.

What are the four phases of the menstrual cycle? The menstrual cycle has four phases: the menstrual phase, the follicular phase, the ovulatory phase, and the luteal phase. Each phase is characterised by different hormone levels, which influence energy, mood, concentration, and physical capacity. Most people think of their cycle in terms of "period" and "not period", but understanding all four phases is what makes cycle-aware planning possible. Nadi's menstrual cycle calendar tool maps all four phases onto your calendar.

What happens during the menstrual phase? The menstrual phase begins on day one of your period and typically lasts three to seven days. Oestrogen and progesterone are at their lowest levels during this phase, which often results in lower energy, increased sensitivity, and a natural pull toward rest. Many women find this a useful time for reflection, slower-paced work, and reduced social commitments — rather than pushing through at full capacity.

What happens during the follicular phase? The follicular phase begins on day one of your period and extends until ovulation — typically days one to fourteen in a 28-day cycle, though this varies. As oestrogen rises during this phase, most women experience increasing energy, sharper focus, and greater motivation. Research suggests brain activity associated with reward and goal-directed behaviour is heightened during the follicular phase. This is often a good time for starting new projects, creative work, and tackling complex tasks.

What happens during the ovulatory phase? The ovulatory phase is typically a short window of one to two days, occurring around the midpoint of your cycle. A surge in luteinising hormone triggers the release of an egg. Oestrogen peaks during this phase and testosterone also rises, often producing heightened energy, outward focus, and confidence. Many women find this the most naturally social and communicative time of their cycle — well-suited to important meetings, presentations, and difficult conversations.

What happens during the luteal phase? The luteal phase runs from after ovulation until the start of your next period — typically around fourteen days, though research shows significant individual variation. Progesterone rises to prepare the uterine lining for potential pregnancy. As progesterone peaks and then drops toward the end of this phase, many women experience lower energy, reduced sociability, increased sensitivity, and PMS symptoms. This phase is often characterised by a more inward, detail-focused quality that can be useful for administrative tasks, editing, and planning work.

Why do I feel so tired during my period? During menstruation, oestrogen and progesterone drop to their lowest levels, which naturally reduces energy. Your body is also directing physical resources toward shedding the uterine lining. This tiredness is not a sign of weakness — it is a physiological response. Understanding it through a menstrual cycle calendar tool can help you plan accordingly rather than fight it.

Why do I have more energy at certain times of the month? Energy naturally fluctuates across the menstrual cycle in response to hormonal changes. Oestrogen rises during the follicular phase, which is associated with improved mood, motivation, and cognitive sharpness. This peaks around ovulation. Progesterone's rise during the luteal phase has a calming but sometimes depleting effect. Rather than experiencing this as inconsistency, understanding the pattern through a menstrual cycle calendar tool allows women to plan energy-intensive tasks for higher-energy phases and protect lower-energy days.

Is the luteal phase always 14 days? This is a common assumption, but the research says otherwise. A large-scale study of over 612,000 cycles found the average luteal phase was 12.4 days, with a range of 7 to 17 days. A 2024 study published in Human Reproduction found that 55% of women experienced at least one short luteal phase during a year of tracking. In the current version of Nadi, phase calculations are based on the averages and the data inputted at setup rather than your individual luteal phase length — so it is worth bearing this in mind as you use the calendar and observe your own patterns over time.

References: Bull, J.R. et al. (2019). npj Digital Medicine, 2, 83. Henry, S. et al. (2024). Human Reproduction, 39(11), 2565-2574.

Why do I feel anxious or low before my period? In the late luteal phase, oestrogen and progesterone both decline sharply. Oestrogen is linked to serotonin production, so its drop can affect mood - increasing anxiety, irritability, or low feelings. This is the hormonal basis of PMS. Understanding that these feelings are often cyclical and predictable is one of the most useful things a menstrual cycle calendar tool can offer. When you can see the phase on your calendar, you can plan lighter social and work commitments and respond to yourself with more compassion rather than self-criticism. If mood changes are severe or significantly disrupt daily life, this may indicate PMDD and is worth discussing with a healthcare professional. Nadi provides awareness, not diagnosis.

How does my menstrual cycle affect my mood at work? Research consistently shows that menstrual cycle phases influence mood, concentration, and energy at work. During the follicular and ovulatory phases, rising oestrogen is associated with improved mood, sharper focus, and greater confidence. During the late luteal phase, declining hormones can increase emotional sensitivity, reduce resilience, and lower motivation. A 2022 study of 1,867 women found that 86.9% reported a moderate to severe impact of their cycle on mood at work. Awareness of these patterns — supported by a menstrual cycle calendar tool — allows women to plan accordingly rather than conclude something is wrong with them.

Why do I feel like a different person every week? You are not imagining it. Across a typical cycle, oestrogen, progesterone, and testosterone all fluctuate significantly — and these hormones affect mood, cognition, social behaviour, and physical energy. The experience of feeling energised and outward-facing one week and withdrawn and depleted the next is a real hormonal pattern, not inconsistency. Understanding your cycle phases through a menstrual cycle calendar tool helps you recognise these shifts as predictable and useful signals rather than personal failings.

Does tracking my cycle help with PMS? Cycle tracking does not treat PMS, but research and lived experience both suggest that awareness reduces its impact. When you can anticipate the phases of your cycle using a menstrual cycle calendar tool, you can adjust your schedule, reduce high-pressure commitments during the late luteal phase, and approach symptoms with self-compassion rather than confusion. If PMS symptoms are severe, a healthcare professional can offer medical options. Nadi supports awareness — not treatment.

Can my menstrual cycle affect my confidence? Yes — and understanding this is useful, not limiting. Research links the ovulatory phase, when oestrogen peaks, to increased confidence, verbal fluency, and social engagement. The late luteal phase, when hormones drop, can bring greater self-criticism and lower confidence. Knowing where you are in your cycle does not determine what you can do — but it can help you prepare, time high-stakes activities more intentionally, and be kinder to yourself on harder days.

How do I plan my work around my menstrual cycle? Cycle-aware planning means using your four cycle phases as a loose framework for scheduling — not a rigid rulebook. During the follicular phase, energy and focus tend to rise, making it a good time for complex tasks, new projects, and creative work. The ovulatory phase often brings peak confidence and communication, well-suited to important meetings or presentations. The luteal phase suits detail work, editing, and administration. The menstrual phase calls for rest and lighter demands. Nadi's menstrual cycle calendar tool overlays these phases directly onto Google or Apple Calendar so you can see your cycle as you plan your week.

What tasks should I prioritise in each phase of my menstrual cycle? This is a general guide - your personal patterns matter more than averages. During the menstrual phase: rest, reflection, slower-paced tasks. During the follicular phase: learning, creative work, starting new projects, high-focus tasks. During the ovulatory phase: important meetings, networking, presentations, difficult conversations. During the luteal phase: editing, administration, reviewing, planning work, and self-care as energy begins to drop. Nadi's menstrual cycle calendar tool helps you see which phase you are in so you can make these decisions with awareness.

Is it realistic to plan my work around my cycle every month? Cycle-aware planning is not about perfect alignment — it is about having information you did not have before. Even small adjustments, like scheduling a high-stakes presentation during your follicular or ovulatory phase rather than the late luteal phase, or protecting energy during menstruation, can make a meaningful difference. It also reduces self-criticism when productivity fluctuates. Nadi is designed to make this practical — not to add another system to manage.

How far in advance can I plan around my menstrual cycle? With Nadi's menstrual cycle calendar tool overlaid onto your Google or Apple Calendar, you can see your estimated cycle phases weeks and months ahead. This means you can plan important work events, travel, or personal commitments with your cycle in mind — avoiding known low-energy windows where possible and protecting space for recovery. The more you use it, the more you learn your own patterns.

Do I need a regular cycle to use Nadi? Nadi works best for women with broadly predictable cycles, as it calculates your phases based on the averages you provide at setup — your last period date, average cycle length, and average period length. If your cycle varies significantly month to month, the phase estimates will be less accurate unless you update your inputs when your cycle changes. That said, even an approximate phase map can be a useful planning reference. Understanding the general shape of your cycle — even imperfectly — is more than most women have access to. We hope to introduce more flexible cycle tracking in future versions of Nadi to better support women with irregular cycles.

How does the menstrual cycle affect work performance? Research consistently shows that menstrual cycle symptoms affect women's concentration, energy, efficiency, and mood at work. A 2022 study of 1,867 women found that 89.3% reported a moderate to severe negative impact on energy levels, and 45.2% had missed at least one day of work in the previous year due to their menstrual cycle. Despite this, only 12% of organisations provide any form of menstrual health support. Cycle awareness — including tools like Nadi's menstrual cycle calendar tool — can help women plan around these fluctuations rather than simply absorb them.

What is menstrual health in the workplace? Menstrual health in the workplace refers to the policies, culture, and tools that support employees who menstruate to do their jobs without unnecessary disadvantage or stigma. This includes flexible working arrangements, access to menstrual products, training for managers, and awareness education — such as Nadi's workplace education sessions on cycle-aware working. CIPD research found that two-thirds of women with symptoms experience a negative impact at work, yet most employers provide no support at all.

What is cycle-aware working and how do workplaces implement it? Cycle-aware working means recognising that women's energy, focus, and capacity naturally vary across their menstrual cycle phases, and designing work culture to accommodate this rather than ignore it. For workplaces, this might include flexible scheduling, manager training on menstrual health, and access to education tools like Nadi's menstrual cycle calendar tool and workplace workshops. It does not require disclosure of personal health information — it requires a culture that normalises natural variation.

How can HR teams support employees with their menstrual cycle? HR teams can support employees in several practical ways: implementing a menstrual health policy, training line managers to respond sensitively, offering flexible working arrangements, ensuring access to menstrual products at work, and providing education resources about cycle-aware working. Nadi works with organisations to deliver menstrual health education and training for teams, and supports employees with practical planning tools. Research shows 94.4% of women would or might be willing to participate in menstrual health programming if it were offered.

Should employers offer menstrual health support? There is a growing evidence base and business case for doing so. CIPD research found that 3% of women have already left a job due to lack of menstrual health support, with a further 5% considering it. In June 2023, the British Standards Institute published landmark guidance on menstruation and menopause in the workplace. Beyond retention, supporting menstrual health reduces absenteeism, improves wellbeing, and signals a genuinely inclusive culture. Nadi's workplace offer supports organisations in building this practically.

How does Nadi calculate which phase I am in? Nadi uses three inputs you provide: your last period start date, your average period length, and your average cycle length. From these, it calculates your four phases — menstrual, follicular, ovulatory, and luteal. The ovulatory window is placed 19 days before your next predicted period, based on peer-reviewed research establishing that ovulation typically occurs 12 to 16 days before menstruation begins. This calendar-based approach is the same methodology that underpins the wider cycle tracking industry. In this version of Nadi, phase calculations are based on the averages you provide at setup. We hope to introduce more personalised cycle learning in future versions, so that phase estimates can adapt as Nadi learns your individual patterns over time. Nadi is a planning tool — not an ovulation predictor or contraceptive method.

Is Nadi's cycle calculation based on research? Yes. The core approach is grounded in peer-reviewed research. The ovulatory window used by Nadi is based on landmark studies establishing that conception can only occur during the five days before ovulation plus the day of ovulation itself. This was confirmed in follow-up research analysing 696 cycles using urinary hormone markers.

References: Wilcox, A.J., Weinberg, C.R., & Baird, D.D. (1995). New England Journal of Medicine, 333(23), 1517-1521. Wilcox, A.J., Dunson, D., & Baird, D.D. (2000). BMJ, 321(7271), 1259-1262.

How accurate are Nadi's cycle phase predictions? Nadi provides estimates based on your averages — not precise physiological predictions. Research confirms that no calendar-based method can pinpoint the exact day of ovulation. Only methods using physiological markers such as hormone testing or basal body temperature can do that. What Nadi offers is a research-grounded framework for understanding your cycle phases and planning with awareness — not a medical diagnostic tool.

Reference: Johnson, S., Marriott, L., & Zinaman, M. (2018). Current Medical Research and Opinion, 34(9), 1587-1594.

Should I use Nadi for contraception or to try to conceive? No. Nadi is a cycle awareness and wellbeing tool. It is designed to help you understand your patterns and plan your life — not to replace medical advice or contraception. For precise ovulation detection, please speak to a healthcare professional about methods that use physiological markers such as hormone testing or basal body temperature monitoring.

Is Nadi medical advice? No. Nadi provides education and awareness — not diagnosis, treatment, or contraceptive guidance. Our content is designed to help women understand their cycles and plan more effectively. We always encourage professional medical support where symptoms are severe, persistent, or causing significant disruption to daily life.

What does Nadi not do? Nadi does not diagnose health conditions, treat menstrual disorders, or provide contraception. It does not replace a healthcare professional. If you experience severe pain, irregular cycles with no identifiable pattern, or mood changes that significantly disrupt your daily life, please consult a doctor. Nadi supports awareness and planning — it is not a medical tool. Conditions including endometriosis, PCOS, and PMDD require medical assessment. Awareness tools like Nadi can support you in noticing patterns worth discussing with a professional, but cannot diagnose or treat these conditions.

Wilcox, A.J., Weinberg, C.R., & Baird, D.D. (1995). New England Journal of Medicine, 333(23), 1517-1521.

Wilcox, A.J., Dunson, D., & Baird, D.D. (2000). BMJ, 321(7271), 1259-1262.

Bull, J.R. et al. (2019). npj Digital Medicine, 2, 83.

Henry, S. et al. (2024). Human Reproduction, 39(11), 2565-2574.

Johnson, S., Marriott, L., & Zinaman, M. (2018). Current Medical Research and Opinion, 34(9), 1587-1594.

Ponzo, S. et al. (2022). Menstrual cycle-associated symptoms and workplace productivity. SAGE Open Medicine.

Sihanath, W.B. et al. (2025). A survey assessing the impact of symptoms related to the menstrual cycle and perceptions of workplace productivity: considerations for employer-sponsored menstrual health programs. BMC Women's Health, 25, 418.

CIPD. (2023). Menstruation and support at work.