☾ Late Period Calculator
Calculate the exact number of days your period is delayed and find potential causes.
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Start Free AI Coaching ✦🧬 Why is My Period Late? Common Causes Explained
A delayed period is a common concern. While pregnancy is the first cause that comes to mind, several lifestyle, physical, and psychological factors can cause your menstrual cycle to run late.
✦ How many days of delay is considered normal? ↓
A delay of 1 to 7 days is completely normal. Factors like temporary stress, illness, changes in sleep, or travel can delay ovulation, pushing back your period. If your period is delayed by more than 7 days, it's considered late.
✦ Can intensive workouts or dieting delay my period? ↓
Yes, high-intensity exercise paired with low calorie intake causes hypothalamic amenorrhea. When the brain senses a severe energy deficit, it stops producing gonadotropin-releasing hormone (GnRH), pausing ovulation.
✦ When should I take a pregnancy test? ↓
You can take a urine home pregnancy test from the first day of your expected period. If the test is negative and your period still hasn't arrived after a week, repeat the test or get a blood hCG test.
✦ Can weight changes cause a late period? ↓
Both rapid weight loss and significant weight gain can disrupt menstruation. Losing more than 10% of body weight in a short period often triggers hypothalamic amenorrhea, where the brain suppresses reproductive hormones. Excess weight increases estrogen production from fat tissue, which can interfere with the normal feedback loop and delay or skip ovulation.
✦ Does travel or jet lag delay periods? ↓
Crossing multiple time zones disrupts your circadian rhythm, which is tightly linked to the hypothalamic-pituitary-ovarian axis. Studies show that shift workers and frequent travelers have a higher incidence of cycle irregularity. The effect is usually temporary — lasting one to two cycles — as your body readjusts to a stable light-dark schedule.
✦ Can stopping birth control cause late periods? ↓
Yes. After discontinuing hormonal contraceptives, it can take 1–3 months for natural ovulation to resume — a phenomenon called post-pill amenorrhea. This is more common after long-term use (5+ years) or with injectable contraceptives like Depo-Provera, where the return to regular cycles can take up to 12 months.
📖 How to Use the Late Period Calculator
Enter the date your period was expected to start based on your usual cycle length. The calculator computes how many days have passed since that expected date to quantify the delay.
If you're unsure of the exact expected date, add your average cycle length to the first day of your last period. A 28-day cycle that started January 1 would predict the next period on January 29.
📊 What the Numbers Mean
A delay of 1–7 days falls within normal biological variation — cycles are rarely identical month to month. Delays of 8–14 days suggest ovulation may have been pushed back by stress, illness, or lifestyle changes. Delays beyond 14 days warrant further attention.
The status indicator categorizes your delay as normal variation, delayed, or potential amenorrhea (90+ days). Each category comes with a recommended action tailored to the level of clinical concern.
⚕️ When to Consult Your Doctor
Schedule a medical appointment if your period is more than 14 days late and a pregnancy test is negative, if you miss three or more periods in a row, or if late periods are accompanied by unexplained weight gain, excessive hair growth, or severe acne. These symptoms may point to PCOS, thyroid disorders, or hypothalamic amenorrhea — all of which are treatable when diagnosed early.