Accurately estimate your baby's due date using last menstrual period (LMP), conception date, IVF transfer, or ultrasound dating. Evidence-based, WCAG-accessible, and mobile-first due date calculator.
Estimate your baby’s due date from LMP, conception, IVF transfer, or ultrasound dating, with cycle-length adjustments and key milestones.
Interactive Calculator
Enter your typical cycle length. If unknown, leave at 28 days. The estimate adjusts for cycles shorter/longer than 28 days.
days
If unsure, use the LMP method instead.
Common options: Day-3 (cleavage-stage) or Day-5 (blastocyst). EDD = transfer date + (266 − embryo age in days).
days
Enter weeks+days reported on your ultrasound report, e.g., 10 weeks 4 days.
Results
Estimated due date (EDD)—
Gestational age today—
Days until due date—
Trimester—
Data Source and Methodology
Authoritative sources:
American College of Obstetricians and Gynecologists (ACOG). Methods for Estimating the Due Date. Committee Opinion No. 700. First issued May 2017; reaffirmed 2024. Read the guidance.
All computations implement Naegele’s rule and ACOG-aligned ultrasound dating adjustments. All calculations are for education only and do not replace clinical judgment.
Tutti i calcoli si basano rigorosamente sulle formule e sui dati forniti da questa fonte.
CycleLength: Usual length of menstrual cycle in days; standard assumption is 28.
EDD: Estimated Due Date—40 weeks of gestation (280 days from LMP).
ConceptionDate: Ovulation/fertilization date (about 14 days after LMP in a 28-day cycle).
TransferDate: IVF embryo transfer date (day-3 or day-5 most common).
EmbryoAgeDays: Age of embryo at transfer in days (e.g., 3 or 5).
ScanDate: Date an ultrasound measured gestational age.
GA_w, GA_d: Gestational age at ultrasound in weeks and days.
How It Works: A Step-by-Step Example
Scenario: LMP on July 1, 2024, with a 30-day cycle.
Start with Naegele’s rule: add 280 days to LMP.
Adjust for cycle length: 30 − 28 = +2 days.
Total offset = 282 days.
EDD = 2024-07-01 + 282 days = April 9, 2025.
This matches the LMP formula: EDD = LMP + 280 + (30 - 28).
Frequently Asked Questions (FAQ)
Which method should I choose?
LMP is appropriate for regular cycles with a known start date. Use Conception if you know the exact ovulation date. For IVF, use the transfer method. If you have a first-trimester ultrasound, Ultrasound dating is typically most accurate.
How accurate is the due date?
Only a small percentage deliver exactly on the date. Most births occur within two weeks before or after. Ultrasounds in the first trimester offer the most precise dating.
Can I use this with irregular cycles?
Yes, but accuracy may be reduced. If cycles vary widely, an early ultrasound or clinician guidance is recommended.
What if my ultrasound date differs from LMP?
Clinicians often prioritize early ultrasound if discrepancy exceeds accepted thresholds (per ACOG criteria). Always follow your provider’s advice.
How do IVF day-3 vs day-5 transfers change EDD?
EDD = transfer date + (266 − embryo age in days). Day-3 → +263 days; Day-5 → +261 days.
Is this medical advice?
No—this is an educational estimate and not a substitute for professional medical advice.
Audit: CompleteFormula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Estimate your baby’s due date from LMP, conception, IVF transfer, or ultrasound dating, with cycle-length adjustments and key milestones.
Interactive Calculator
Enter your typical cycle length. If unknown, leave at 28 days. The estimate adjusts for cycles shorter/longer than 28 days.
days
If unsure, use the LMP method instead.
Common options: Day-3 (cleavage-stage) or Day-5 (blastocyst). EDD = transfer date + (266 − embryo age in days).
days
Enter weeks+days reported on your ultrasound report, e.g., 10 weeks 4 days.
Results
Estimated due date (EDD)—
Gestational age today—
Days until due date—
Trimester—
Data Source and Methodology
Authoritative sources:
American College of Obstetricians and Gynecologists (ACOG). Methods for Estimating the Due Date. Committee Opinion No. 700. First issued May 2017; reaffirmed 2024. Read the guidance.
All computations implement Naegele’s rule and ACOG-aligned ultrasound dating adjustments. All calculations are for education only and do not replace clinical judgment.
Tutti i calcoli si basano rigorosamente sulle formule e sui dati forniti da questa fonte.
CycleLength: Usual length of menstrual cycle in days; standard assumption is 28.
EDD: Estimated Due Date—40 weeks of gestation (280 days from LMP).
ConceptionDate: Ovulation/fertilization date (about 14 days after LMP in a 28-day cycle).
TransferDate: IVF embryo transfer date (day-3 or day-5 most common).
EmbryoAgeDays: Age of embryo at transfer in days (e.g., 3 or 5).
ScanDate: Date an ultrasound measured gestational age.
GA_w, GA_d: Gestational age at ultrasound in weeks and days.
How It Works: A Step-by-Step Example
Scenario: LMP on July 1, 2024, with a 30-day cycle.
Start with Naegele’s rule: add 280 days to LMP.
Adjust for cycle length: 30 − 28 = +2 days.
Total offset = 282 days.
EDD = 2024-07-01 + 282 days = April 9, 2025.
This matches the LMP formula: EDD = LMP + 280 + (30 - 28).
Frequently Asked Questions (FAQ)
Which method should I choose?
LMP is appropriate for regular cycles with a known start date. Use Conception if you know the exact ovulation date. For IVF, use the transfer method. If you have a first-trimester ultrasound, Ultrasound dating is typically most accurate.
How accurate is the due date?
Only a small percentage deliver exactly on the date. Most births occur within two weeks before or after. Ultrasounds in the first trimester offer the most precise dating.
Can I use this with irregular cycles?
Yes, but accuracy may be reduced. If cycles vary widely, an early ultrasound or clinician guidance is recommended.
What if my ultrasound date differs from LMP?
Clinicians often prioritize early ultrasound if discrepancy exceeds accepted thresholds (per ACOG criteria). Always follow your provider’s advice.
How do IVF day-3 vs day-5 transfers change EDD?
EDD = transfer date + (266 − embryo age in days). Day-3 → +263 days; Day-5 → +261 days.
Is this medical advice?
No—this is an educational estimate and not a substitute for professional medical advice.
Audit: CompleteFormula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Estimate your baby’s due date from LMP, conception, IVF transfer, or ultrasound dating, with cycle-length adjustments and key milestones.
Interactive Calculator
Enter your typical cycle length. If unknown, leave at 28 days. The estimate adjusts for cycles shorter/longer than 28 days.
days
If unsure, use the LMP method instead.
Common options: Day-3 (cleavage-stage) or Day-5 (blastocyst). EDD = transfer date + (266 − embryo age in days).
days
Enter weeks+days reported on your ultrasound report, e.g., 10 weeks 4 days.
Results
Estimated due date (EDD)—
Gestational age today—
Days until due date—
Trimester—
Data Source and Methodology
Authoritative sources:
American College of Obstetricians and Gynecologists (ACOG). Methods for Estimating the Due Date. Committee Opinion No. 700. First issued May 2017; reaffirmed 2024. Read the guidance.
All computations implement Naegele’s rule and ACOG-aligned ultrasound dating adjustments. All calculations are for education only and do not replace clinical judgment.
Tutti i calcoli si basano rigorosamente sulle formule e sui dati forniti da questa fonte.
CycleLength: Usual length of menstrual cycle in days; standard assumption is 28.
EDD: Estimated Due Date—40 weeks of gestation (280 days from LMP).
ConceptionDate: Ovulation/fertilization date (about 14 days after LMP in a 28-day cycle).
TransferDate: IVF embryo transfer date (day-3 or day-5 most common).
EmbryoAgeDays: Age of embryo at transfer in days (e.g., 3 or 5).
ScanDate: Date an ultrasound measured gestational age.
GA_w, GA_d: Gestational age at ultrasound in weeks and days.
How It Works: A Step-by-Step Example
Scenario: LMP on July 1, 2024, with a 30-day cycle.
Start with Naegele’s rule: add 280 days to LMP.
Adjust for cycle length: 30 − 28 = +2 days.
Total offset = 282 days.
EDD = 2024-07-01 + 282 days = April 9, 2025.
This matches the LMP formula: EDD = LMP + 280 + (30 - 28).
Frequently Asked Questions (FAQ)
Which method should I choose?
LMP is appropriate for regular cycles with a known start date. Use Conception if you know the exact ovulation date. For IVF, use the transfer method. If you have a first-trimester ultrasound, Ultrasound dating is typically most accurate.
How accurate is the due date?
Only a small percentage deliver exactly on the date. Most births occur within two weeks before or after. Ultrasounds in the first trimester offer the most precise dating.
Can I use this with irregular cycles?
Yes, but accuracy may be reduced. If cycles vary widely, an early ultrasound or clinician guidance is recommended.
What if my ultrasound date differs from LMP?
Clinicians often prioritize early ultrasound if discrepancy exceeds accepted thresholds (per ACOG criteria). Always follow your provider’s advice.
How do IVF day-3 vs day-5 transfers change EDD?
EDD = transfer date + (266 − embryo age in days). Day-3 → +263 days; Day-5 → +261 days.
Is this medical advice?
No—this is an educational estimate and not a substitute for professional medical advice.
Audit: CompleteFormula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.