Next Period Calculator: When Is My Next Period?

Predict your next period with a 3-day window from your last period date and average cycle length. You also get the next two start dates, today’s cycle day, a late flag, and the earliest reliable test day if late. Last period start date If left blank, the calculator will assume 28 days ago. Average cycle … Read more

Vasectomy Failure Risk Calculator

Vasectomy is very effective, but failures can happen—most early (before semen analysis is clear) and rarely years later from recanalization. This calculator estimates annual and cumulative risk bands using your procedure type and time since surgery. It’s educational only; if your partner’s period is late, test early and speak with a clinician. Months since vasectomy … Read more

Tubal Ligation Failure Risk Calculator

Tubal ligation is very effective, but failures can occur—and when they do, ectopic pregnancy is more likely. This calculator estimates your annual and cumulative risk bands based on procedure type, time since surgery, and whether a reversal was done. Use it for education only; if you have pregnancy symptoms, test early and contact a clinician. … Read more

Clomiphene/Letrozole Ovulation Day Calculator

Use this calculator to estimate when you’re most likely to ovulate after a cycle of clomiphene (e.g. Clomid) or Letrozole (e.g. Femara). Enter your regimen and last pill date to get a likely ovulation window, the earliest reliable test day, and an estimated due date if you conceive. Educational only—timing varies and clinical monitoring is … Read more

OPK-to-Ovulation Timing Calculator

Got a positive LH test and wondering when you’ll ovulate? Enter the time of your first positive OPK and your typical surge length. This tool estimates your ovulation window, highlights the best days to try, and suggests the first reliable pregnancy test day—plus your estimated due date if you conceive. Date of first positive OPK … Read more

Late Period or Pregnant? Probability Calculator

A missed or late period can be stressful. This calculator weighs your cycle history, how many days late you are, recent protected or unprotected intercourse, and any test dates to estimate whether pregnancy or a delayed cycle is more likely-plus when to test or retest for the most reliable result. Not sure when your period … Read more

Breastfeeding (LAM) Eligibility & Risk Calculator

Check if you meet LAM (Lactational Amenorrhea Method) criteria while breastfeeding. Enter baby’s age, feeding pattern, night feeds, and period status to see if LAM applies, how effective it is, and when to switch methods. Baby’s age (months) Exclusive breastfeeding (%) 100% Approximate how much of baby’s intake is breast milk (no regular formula/solids = … Read more

IUI Success Rate Calculator

Estimate your IUI pregnancy chance using age, trigger use, semen quality (normal or low), and which attempt you’re on. See per-cycle probability and cumulative odds estimates across the first three IUIs. Female Age IUIs this cycle Single IUIDouble IUI (two inseminations this cycle) Semen Quality (quick) Auto — use detailed values if enteredNormal parametersLow count/motility … Read more

Chance of Twins Calculator

Reviewed by Dr. Sony Sherpa, MBBS, MD on Dec 22, 2025 Estimate your likelihood of twins based on age, family history (maternal side), height/BMI, ethnicity, prior pregnancies, fertility treatment, and past twins. Results show a baseline risk with a fraternal (dizygotic) vs identical (monozygotic) split, using population studies. Basics Female age Prior births Family history … Read more

Implantation vs Period Calculator

Enter cycle timing and symptoms to see your chances of implantation vs period and when to test next. Timing Do you know your ovulation date? NoYes Start date of your last period (LMP) Average cycle length (days) Ovulation date Bleeding started on Bleeding details Pattern (pick the closest) Only when wipingSpotting on underwearLight flowModerate flowHeavy … Read more