Current Gestation Calculator

Measure pregnancy timing from key clinical dates accurately. View progress, due date, and milestones clearly. Built for simple weekly pregnancy tracking.

Calculator Inputs

Use your average cycle length in days.

Example Data Table

Case Method Reference Input Cycle Length Calculated Gestation Estimated Due Date
Example A LMP 2026-01-10 28 days Calculated from today LMP + 280 days
Example B Conception 2026-02-01 Not used Conception + 14 days for gestational age basis Conception + 266 days
Example C Ultrasound Scan: 2026-03-01 at 8w 4d Not used Back-calculated from scan age Derived from back-calculated LMP equivalent

Formula Used

1. LMP method: Gestational age in days = today − LMP date.

2. Standard due date: Estimated due date = LMP + 280 days.

3. Cycle adjustment: Adjusted due date = LMP + 280 days + (cycle length − 28).

4. Conception method: Gestational age basis starts about 14 days before conception, so LMP equivalent = conception date − 14 days.

5. Conception due date: Estimated due date = conception date + 266 days.

6. Ultrasound method: LMP equivalent = ultrasound date − gestational age measured on scan.

7. Progress percentage: Pregnancy progress = (gestational days ÷ 280) × 100.

8. Weeks and days format: Weeks = floor(total gestational days ÷ 7), days = total gestational days mod 7.

How to Use This Calculator

  1. Select the dating method that matches the information you have.
  2. Enter the correct date fields for LMP, conception, due date, or ultrasound.
  3. For LMP dating, add your average cycle length if it differs from 28 days.
  4. Choose whether you also want approximate fetal age shown.
  5. Press Calculate Current Gestation to display the result above the form.
  6. Review gestational age, due date, progress percentage, trimester, and milestone.
  7. Use the graph to visualize current pregnancy progress against a 40-week timeline.
  8. Download a CSV summary or save a PDF copy for records.

Frequently Asked Questions

1. What is current gestation?

Current gestation is the pregnancy age counted in weeks and days. It usually starts from the first day of the last menstrual period, not from conception itself.

2. Why is gestational age older than fetal age?

Gestational age usually includes about two weeks before fertilization. Fetal age estimates actual time since conception, so it is commonly around 14 days less.

3. Which dating method is usually preferred?

LMP is common when cycle timing is reliable. Early ultrasound may be more accurate if periods are irregular or the LMP date is uncertain.

4. Does cycle length matter?

Yes. Longer or shorter cycles can shift ovulation timing. Adjusting the due date by the cycle difference improves estimates when the LMP method is used.

5. Is the due date exact?

No. The due date is an estimate based on standard pregnancy timing. Birth can naturally happen before or after that date.

6. Can I use an ultrasound date only?

Yes. Enter the scan date and the gestational age measured on that scan. The calculator back-calculates the pregnancy start point and estimated due date.

7. Why does the calculator show trimesters?

Trimester grouping helps you understand the pregnancy stage quickly. It is useful for milestones, checkups, and general planning across the full term.

8. Is this calculator a medical diagnosis tool?

No. It is an educational estimate tool. Clinical decisions should always follow guidance from a qualified obstetric or prenatal care professional.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.