Conception Calculator

Estimate your conception date and pregnancy timeline.

Introduction

Welcome to the Conception Calculator! This tool helps you estimate your conception date using your last menstrual period (LMP), due date, ultrasound results, or a known conception date. You can also calculate your due date if you know when conception occurred. Visualize your timeline with a calendar and prepare for your baby’s arrival.

Calculation Method:

First Day of Last Menstrual Period:

Cycle Length (days):

Due Date:

Ultrasound Date:

Weeks Pregnant at Ultrasound:

Days Pregnant at Ultrasound:

Conception Date:

How to Use

Select a calculation method: LMP, Due Date, Ultrasound, or Known Conception Date.
Enter the required information in the fields that appear.
Click "Calculate" to see your estimated conception date, intercourse range, and due date.
View the calendar to see the highlighted date ranges (red for conception, blue for intercourse).
Click "Save Calculation" to store your results locally.
Use "Reset" to clear all inputs and start over.

Understanding Conception

When Did Conception Happen?

Conception typically occurs 11-21 days after the first day of your last menstrual period (LMP) in women with regular cycles, around the time of ovulation. This calculator estimates your conception date and provides a range of days when intercourse may have led to conception, accounting for factors like sperm survival (up to 5 days).

Methods Explained

Last Menstrual Period (LMP): Estimates conception by adjusting for your cycle length, typically 14 days after LMP for a 28-day cycle. Less precise for irregular cycles.

Due Date: Calculates conception by subtracting 266 days from your due date, the average time from conception to birth.

Ultrasound: Uses fetal measurements to estimate gestational age, most accurate in early pregnancy (5-6 weeks after LMP).

Known Conception Date: Adds 266 days to estimate your due date.

Fertilization and Conception

Fertilization occurs when a sperm and egg unite in the fallopian tube. Conception involves both fertilization and implantation into the uterine wall, which marks the start of pregnancy medically.

FAQs

How accurate is the conception date estimate?

It’s an estimate based on average ovulation timing. Actual conception can vary due to cycle length, ovulation timing, or other factors.

Can I use this if my cycles are irregular?

Yes, but the estimate may be less accurate. Use the ultrasound method for better precision.

What if I don’t know my LMP?

Use your due date, ultrasound results, or a known conception date instead.

About This Calculator

Built by xAI, this Conception Calculator uses standard medical guidelines to help you understand your pregnancy timeline. For precise details, consult your healthcare provider.