Lunara’s period calculator predicts your next period based on your last period start date and cycle length, helping you stay prepared.
Many people experience symptoms like cramps, breast tenderness, and mood swings. Tracking these in the Lunara app can help you anticipate them.
Even with irregular periods, logging cycle dates and symptoms regularly can help identify patterns to discuss with your doctor.
This calculator offers an estimate, not a guarantee, as various factors can influence your cycle. It should not be used as a contraceptive method.
To use a period calculator like this one, simply enter:
The first day of your last period: This marks the start of a new cycle.
Your average cycle length: Count the days from the first day of your last period to the day before your next one. The average is around 28 days, but anywhere between 21 and 35 days is considered typical.
Lunara’s period calculator will then estimate your next period start date by adding your cycle length to the first day of your last period.
Since cycles can vary due to factors like stress or lifestyle changes, these predictions are only estimates and may shift by a few days.
If your periods are irregular, the predictions may be less precise. However, tracking multiple cycles with an app like Lunara can help you recognize patterns, better understand your body, and provide useful data for discussions with your doctor.
If your periods are irregular, the predictions may be less precise. However, tracking multiple cycles with an app like Lunara can help you recognize patterns, better understand your body, and provide useful data for discussions with your doctor.
This period calculator estimates when your next period might start and end based on the details you provide, like your last period’s start date and cycle length.
However, since factors like stress, weight changes, and illness can affect your cycle, these dates are just a guide—not a guarantee. Keep in mind that this tool isn’t meant for contraception or as a replacement for medical advice.
This period calculator estimates your next period based on details like your last period’s start date and cycle length. The average cycle length is about 28 days, but cycles can range from 21 to 35 days. Most periods last between two and seven days, though this varies from person to person.
A period is considered irregular if it occurs fewer than 21 days or more than 35 days apart, varies significantly in cycle length, or is particularly heavy. Fluctuations are common and can be influenced by factors like stress, weight changes, or conditions like PCOS.
If you’re unsure when your last period was, you can track it by noting the first day of your most recent period—this is “day 1” of your cycle. Apps like Flo or a simple calendar can help you keep a record.
A period is considered late if it’s more than eight days past its expected arrival. Causes for a late period include stress, birth control changes, weight fluctuations, or pregnancy. If your periods are consistently late or irregular, consulting a health care provider may be helpful.
Mild to moderate cramps are common, but severe pain that disrupts daily life affects 5–15% of people. Pain relievers or heating pads can help, but if cramps are intense, consult a doctor for additional support.
Hormonal changes can make you feel more tired than usual. If your periods are heavy, fatigue might be due to low iron levels (anemia). A doctor can check and manage this if needed.
Hormonal shifts can lead to bloating, which usually subsides after your period. If it persists for weeks, seek medical advice.
Emotional changes, irritability, or heightened sensitivity are common due to hormonal fluctuations. Self-care can help, but if mood swings feel extreme, consider consulting a doctor.
Increased oil production due to hormone changes may trigger acne before or during your period. This usually lasts a few days.
Hormonal shifts can make breasts feel sore, either around ovulation or during your period. This is normal, but if pain is severe, seek medical advice.
Knowing your cycle helps you prepare for changes and gain better insight into your body.
Lunara’s cycle calculator estimates your next cycle based on your last one, but logging regularly allows it to refine predictions for cycle dates, symptoms, and fertility.
“Tracking your cycles provides valuable data,” says Dr. Twogood. “It helps pinpoint patterns and turns vague concerns like ‘My cycle is irregular’ into specific insights for doctors.”