Mensperiodkalkulator – Menscykelspårare
Predict your next period date based on your last menstrual period and average cycle length. Free menstrual cycle calculator.
Slik bruker du denne kalkulatoren
- Skriv inn Last Period Start Date
- Skriv inn Average Cycle Length (days)
- Klikk på Beregn-knappen
- Les resultatet som vises under kalkulatoren
How the Period Calculator Works
This period calculator predicts your next menstrual period based on your last period start date and average cycle length.
The formula is simple: Next period = Last period date + Cycle length (days). The average menstrual cycle is 28 days, but normal cycles range from 21 to 35 days.
The calculator also estimates your ovulation date, which typically occurs about 14 days before your next period.
Understanding Your Menstrual Cycle
The menstrual cycle has four phases:
- Menstruation (Days 1-5): Period bleeding
- Follicular phase (Days 1-13): Egg develops in ovary
- Ovulation (Day ~14): Egg released
- Luteal phase (Days 15-28): Body prepares for potential pregnancy
Tracking your cycle helps with family planning, health monitoring, and understanding your body's patterns.
When to See a Doctor
Consult a healthcare provider if your periods are very irregular, extremely painful, very heavy, last more than 7 days, or if you miss periods without pregnancy.
Note: This calculator provides estimates only and should not be used as a sole method of birth control or fertility planning.
Sist oppdatert: March 2026
Frequently Asked Questions
What is a normal cycle length?
A normal menstrual cycle ranges from 21 to 35 days, with 28 days being the average. Cycles can vary month to month by a few days.
When do I ovulate?
Ovulation typically occurs about 14 days before your next period. For a 28-day cycle, that's around day 14. For a 30-day cycle, around day 16.
Is this calculator accurate for birth control?
No. This calculator provides estimates only and should not be relied upon for birth control. Menstrual cycles can be irregular, and many factors affect timing.