Pregnancy Date Planner Calculator

Planner inputs

Calculation method

LMP date

Cycle length (days)

Conception date

Transfer date

Embryo age at transfer

Ultrasound date

Gestational weeks at ultrasound

Additional gestational days

Known due date

Reference date for progress

Use the method that matches your medical record. This planner supports natural conception, IVF transfer timing, ultrasound dating, and backward planning from a known due date.

Example data table

Scenario	Input basis	Estimated due date	First trimester ends	Anatomy scan target
Regular 28-day cycle	LMP: Jan 10, 2026	Oct 17, 2026	Apr 17, 2026	May 30, 2026
Known conception date	Conception: Feb 01, 2026	Oct 25, 2026	Apr 25, 2026	Jun 07, 2026
IVF blastocyst transfer	Transfer: Mar 03, 2026, embryo age: 5	Nov 19, 2026	May 19, 2026	Jul 02, 2026

Formula used

LMP method: Estimated due date = LMP + 280 days + (cycle length − 28). This follows Naegele-style planning with a cycle-length adjustment.

Conception method: Estimated due date = conception date + 266 days. Approximate LMP = conception date − 14 days.

IVF transfer method: Estimated due date = transfer date + (266 − embryo age in days). This aligns due dating with embryo development before transfer.

Ultrasound method: Estimated due date = ultrasound date + (280 − gestational age in days at scan). Approximate LMP = ultrasound date − gestational age in days.

Gestational age: Gestational age in days = reference date − estimated LMP. Weeks = floor(days ÷ 7), remaining days = days mod 7.

How to use this calculator

Select the dating method that matches your available record.
Enter the relevant date fields, plus cycle length or embryo age when needed.
Choose a reference date to measure current gestational progress.
Press Calculate Planner to show the result above the form.
Review the due date, trimester, milestone schedule, and progress summary.
Download CSV for spreadsheets or PDF for appointment notes and printed planning.

FAQs

1. Which method is most accurate?

Accuracy depends on the clinical information you have. IVF transfer dates and early ultrasounds are often very reliable. LMP-based planning is useful when cycles are regular and dates are remembered clearly.

2. Why does cycle length change the due date?

Longer or shorter cycles can shift ovulation timing. Adjusting by cycle length helps align the estimate with when conception likely happened rather than assuming a standard 28-day cycle.

3. Why is pregnancy counted from LMP instead of conception?

Gestational age is traditionally counted from the first day of the last menstrual period. This standard makes dating consistent across visits, charts, and guideline-based milestone timing.

4. Can I use this for IVF or frozen embryo transfer?

Yes. Choose the IVF or embryo transfer method and enter the transfer date plus embryo age. The planner adjusts the due date and milestone schedule from that fertility timeline.

5. Does this replace my doctor’s due date?

No. This tool is for planning and record keeping. Your clinician may revise dating based on ultrasound findings, fertility records, or pregnancy-specific medical considerations.

6. Why can my ultrasound due date differ from LMP?

Ovulation may not have happened when cycle averages predict. Ultrasound dating measures fetal development directly, so it can shift the timeline when menstrual-cycle assumptions were inaccurate.

7. What does the progress percentage mean?

The progress value compares estimated gestational days with a 280-day pregnancy model. It is a planning aid only and should not be used alone for clinical decisions.

8. What should I do with the CSV and PDF files?

Use CSV for spreadsheet tracking and PDF for printed notes, visit prep, or sharing dates with family. They make milestone planning easier without reentering information later.