Positive Pregnancy Test
Calculate your gestational age and due date after a positive pregnancy test. Enter your LMP and test date for pregnancy timeline, trimester info, hCG ranges, and charts.
About This Calculator
The Positive Pregnancy Test Calculator helps you understand your pregnancy timeline after receiving a positive result. By entering the date of your last menstrual period (LMP) and the date of your positive test, the calculator estimates your current gestational age in weeks and days, your estimated due date, your current trimester, and the typical hCG range for your stage of pregnancy.
Gestational age is calculated from the first day of your last menstrual period, which is the standard medical method for dating pregnancies. Conception typically occurs about two weeks after LMP (around ovulation), so by the time you get a positive test at 4 weeks gestational age, the pregnancy is actually about 2 weeks from conception. The estimated due date uses Naegele's rule: 280 days (40 weeks) from LMP, adjusted for your average cycle length. For a 28-day cycle, the due date is LMP + 280 days; longer or shorter cycles shift the estimate accordingly.
Regional Notes
India: Prenatal care typically begins with a confirmation appointment between 6-8 weeks. The first ultrasound is usually scheduled around 8-12 weeks. Government health programs provide free prenatal supplements and checkups.
United States: Most OB-GYN practices schedule the first prenatal visit between 8-10 weeks. Early ultrasound dating is standard practice. Insurance typically covers prenatal care including screenings and supplements.
United Kingdom: The NHS offers a dating scan between 10-14 weeks and the first midwife appointment (booking appointment) around 8-10 weeks. Free folic acid and vitamin D supplements are available for eligible women.
Frequently Asked Questions
How is gestational age calculated from a positive pregnancy test?
Gestational age is calculated from the first day of your last menstrual period (LMP) to the date of your positive test. Pregnancy is counted from LMP, not from conception, which is typically about 2 weeks before ovulation.
How accurate is the due date calculation?
The due date is estimated as 280 days (40 weeks) from the first day of your last menstrual period, adjusted for cycle length. Only about 5% of babies arrive exactly on their due date; most arrive within a window of 37 to 42 weeks.
What do hCG levels mean after a positive test?
hCG (human chorionic gonadotropin) is a hormone produced during pregnancy. Levels typically double every 48-72 hours in early pregnancy, peaking around 8-11 weeks. The estimated range shown helps you understand if your levels are within typical bounds for your gestational age.
When should I see a doctor after a positive pregnancy test?
You should schedule an appointment with your OB-GYN as soon as possible after a positive test. Early prenatal care helps confirm the pregnancy, estimate due date, screen for potential issues, and start essential supplements like folic acid.
What if my cycle length is irregular?
If you have irregular cycles, the due date estimate may be less accurate. Your doctor may adjust the due date based on early ultrasound measurements, which are most accurate when done between 8-13 weeks of pregnancy.
Can I get a positive test before my missed period?
Yes, some sensitive home pregnancy tests can detect hCG as early as 6-12 days after ovulation (about 4-5 days before your expected period). Blood tests at a clinic can detect pregnancy even earlier.
What should I do immediately after a positive pregnancy test?
Start taking a prenatal vitamin with folic acid, schedule a doctor's appointment, stop alcohol and smoking if applicable, and review any medications with your healthcare provider. Early lifestyle changes support healthy fetal development.
How does the trimester system work?
Pregnancy is divided into three trimesters. First trimester: weeks 1-12 (organ development). Second trimester: weeks 13-27 (growth and movement). Third trimester: weeks 28-40 (final growth and preparation for birth). Each trimester has distinct developmental milestones and prenatal care needs.