An LMP calculator determines important pregnancy dates. Specifically, it calculates your last menstrual period. This tool helps expectant mothers track their pregnancy progress accurately. Doctors also use it to estimate due dates.
Furthermore, this calculator provides conception dates. It assists in prenatal care planning. Additionally, it helps monitor fetal development stages. Many women find it essential for pregnancy management.
LMP stands for Last Menstrual Period. It is the start date of your last period. Importantly, this date is crucial for pregnancy calculations. Doctors use it to estimate gestational age.
Moreover, LMP helps determine your due date. Pregnancy typically lasts 40 weeks from LMP. This calculation assumes a regular 28-day cycle. Remember, actual delivery dates may vary slightly.
First, enter your due date in the field above. Then, click the "Calculate LMP" button. Our calculator will instantly determine your last menstrual period date. Additionally, it will show your conception date and current gestational age.
Moreover, the results include your current trimester. This information helps track your pregnancy progress. Remember, these are estimates. Always consult your healthcare provider for medical advice.
The standard formula for calculating Last Menstrual Period is:
This calculation is based on Naegele's Rule. Pregnancy typically lasts 40 weeks (280 days) from the LMP. The formula assumes a regular 28-day menstrual cycle.
Additionally, conception usually occurs around day 14 of the cycle. Therefore, gestational age is about two weeks more than fetal age. This method is used worldwide by healthcare professionals.
Our LMP calculator uses medical guidelines to determine dates. First, it subtracts 280 days from your due date. This calculates your last menstrual period. The tool also accounts for average cycle length.
Next, it adds 14 days to the LMP for conception date. Then, it calculates gestational age based on current date. Finally, it determines your current trimester. This provides a complete pregnancy timeline overview.
| Gestational Age | Development Stage | Key Milestones | Trimester |
|---|---|---|---|
| 0-4 weeks | Germinal Stage | Fertilization, implantation | First |
| 5-12 weeks | Embryonic Stage | Organ formation begins | First |
| 13-16 weeks | Early Fetal | Sex organs visible | Second |
| 17-26 weeks | Mid Fetal | Movement felt, hearing develops | Second |
| 27-38 weeks | Late Fetal | Rapid growth, lung maturation | Third |
| 39-40 weeks | Full Term | Ready for birth | Third |
LMP calculators provide estimates based on standard pregnancy duration. However, accuracy depends on regular menstrual cycles. Ultrasound measurements offer more precision. Always consult your doctor for confirmation.
For irregular cycles, LMP calculations may be less accurate. Early ultrasound dating is recommended. Track your cycle length for better estimates. Healthcare providers adjust for cycle variations.
Gestational age starts from the LMP, while fetal age begins at conception. Gestational age is typically two weeks more. Medical professionals use gestational age consistently.
Most women know their LMP date precisely. Conception dates are harder to determine. Medical standards use LMP for consistency. This creates a universal reference point.
First trimester: Weeks 1-13. Second: Weeks 14-27. Third: Week 28 until birth. Our calculator automatically categorizes based on gestational age. This helps track development stages.