Pregnancy Week Calculator

Find out exactly how many weeks and days pregnant you are today, explore fetal development, and track trimester milestones.

Calculate Gestational Weeks

Enter your last period date or your estimated due date.

Calculated on your device. Nothing is saved.
Key Takeaway: Gestational age is expressed in completed weeks + days (e.g., 14w 2d means you have completed 14 full weeks and are on the 3rd day of your 15th week).

Trimester Timeline Breakdown

  • First Trimester: Weeks 1 through 13 (+6 days)
  • Second Trimester: Weeks 14 through 27 (+6 days)
  • Third Trimester: Weeks 28 through 40 (+ delivery)

When to See a Doctor

Online calculators provide general estimates based on biological averages. Consult a healthcare provider (such as an OB/GYN or general practitioner) if you notice:

  • Your periods suddenly become irregular after being consistent
  • Your cycle is consistently shorter than 21 days or longer than 35 days
  • Your period bleeding lasts longer than 7 days or is unusually heavy (soaking through a pad/tampon every hour)
  • You experience severe, debilitating pelvic pain or cramping that disrupts daily life
  • You experience bleeding between periods or after intercourse
  • You are under 35 and have been trying to conceive for 12 months (or 6 months if 35+)
  • Your period has stopped completely for 90 days or more (and you are not pregnant)
Next Logical Step

Calculate Pregnancy Calorie Needs

See recommended daily energy intake adjusted for your current trimester.

Open Pregnancy Calorie Calculator

Frequently Asked Questions

Evidence-based answers to common questions about your cycle and fertility.

How do doctors calculate pregnancy weeks?

Doctors count gestational age starting from the first day of your last menstrual period (LMP), meaning you are considered 2 weeks pregnant at the time conception occurs.

Explore other free, private tools for tracking your menstrual cycle and fertility.

Pregnancy & Due Dates

Due Date Calculator

Calculate your estimated baby due date, current gestational age, trimester, and weekly milestones from your LMP, conception, or ultrasound date.

Calculate now
Wellness & Nutrition

Pregnancy Calorie Calculator

Calculate your daily energy and calorie needs by trimester using the Mifflin-St Jeor formula and activity level guidelines. 100% private.

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Wellness & Nutrition

Pregnancy Weight Gain Calculator

Calculate healthy target weight gain ranges and weekly gain rates across each trimester based on your pre-pregnancy BMI and IOM guidance.

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Medical & Scientific Sources

  1. American College of Obstetricians and Gynecologists (ACOG)(2023). "How your fetus grows during pregnancy"
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