Period Calculator India – Predict Your Next Period & Cycle Dates

Your Cycle Details

First Day of Your Last Period

The day your most recent period started (cycle day 1)

Average Cycle Length

28 days

From the first day of one period to the first day of the next. Normal range is 21–35 days.

Period Length

5 days

How many days your bleeding usually lasts.

How prediction works

Your next period is your last period plus your cycle length. We repeat this to project upcoming periods, and mark ovulation about 14 days before each one.

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Enter your last period date above to see your upcoming periods

Understanding Your Menstrual Cycle

A menstrual cycle is counted from the first day of one period to the day before the next period starts. The four phases are:

Menstruation (Days 1–5)

The uterine lining sheds — this is your period. It usually lasts 2–7 days.

Follicular Phase (Days 1–13)

Oestrogen rises and an egg matures. The fertile window opens towards the end of this phase.

Ovulation (≈ Day 14)

An egg is released and is available for fertilisation for 12–24 hours.

Luteal Phase (Days 15–28)

Progesterone rises. If there is no pregnancy, hormones fall and the next period begins. PMS symptoms appear here.

When to See a Doctor

→Very irregular cycles — shorter than 21 days or longer than 35 days regularly.
→Missed periods — three or more in a row without pregnancy.
→Very heavy bleeding — soaking through a pad or tampon every hour, or passing large clots.
→Severe pain — cramps that disrupt daily life or don't respond to usual pain relief.
→Bleeding between periods — or after intercourse, which should always be checked.

Note: This calculator is a general guide for tracking, not a medical diagnosis. Always consult a gynaecologist for persistent concerns.

How Your Period Dates Are Calculated

The calculator uses your average cycle length to project each upcoming period from your last start date:

Next period = Last period + cycle length
Period after that = Last period + (2 × cycle length)
Ovulation = Next period − 14 days

Example

Last period 1 Jan, 28-day cycle → next periods on 29 Jan, 26 Feb, 26 Mar… Ovulation for the current cycle is around 15 Jan.

Frequently Asked Questions

Common questions about period tracking and cycles

How does a period calculator predict my next period?

It adds your average cycle length to the first day of your last period. For a 28-day cycle, your next period is expected 28 days after the last one started. The calculator repeats this to project the next several periods, and also marks your ovulation day and fertile window in each cycle.

What is a normal menstrual cycle length?

A typical cycle is 21 to 35 days, measured from the first day of one period to the first day of the next. The popular '28-day cycle' is just an average. Cycle length can vary by a few days each month and still be perfectly normal, especially in teenagers and women approaching menopause.

Why is my period late or irregular?

Common causes include stress, sudden weight change, intense exercise, travel, thyroid problems, PCOS, certain medications, breastfeeding, and approaching menopause. Pregnancy is also a common reason for a missed period. If your cycles are consistently irregular, consult a gynaecologist.

How accurate is period prediction?

It is most accurate for women with regular cycles. If your cycle length varies a lot from month to month, predictions are only rough estimates. Logging your actual start date every month and updating your average cycle length keeps the forecasts as accurate as possible.

When in my cycle am I most likely to get pregnant?

Your fertile window is the 5 days before ovulation plus ovulation day — about 6 days in total. Ovulation usually happens around 14 days before your next period. The calculator highlights these days so you can plan or avoid pregnancy, though calendar timing alone is not reliable contraception.

What is PMS and when does it happen?

Premenstrual syndrome (PMS) refers to physical and emotional symptoms — bloating, mood changes, cramps, breast tenderness — that appear in the week or so before your period. They are caused by hormonal shifts after ovulation and usually ease once your period begins.

Can I use this calculator to track periods every month?

Yes. Each month, enter the first day of your most recent period and your usual cycle length to see your upcoming period dates, ovulation, and fertile window. For continuous tracking with reminders, a dedicated period-tracking app may be more convenient.

Does cycle length change with age?

Yes. Cycles are often longer and more irregular in the first few years after periods begin, tend to settle into a regular pattern in your 20s and 30s, and may become shorter or more erratic in the years leading up to menopause (perimenopause). Update your average length as it changes.