Implantation Calculator

Estimate your likely implantation date and window from your last period or your ovulation date.

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From Last Period From Ovulation Date

First Day of Your Last Period

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Select Month

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Average Cycle Length (days)

Typically between 21 and 35 days. Count from the first day of one period to the first day of the next.

Luteal Phase Length (days)

The time from ovulation to your next period. 14 days is average if you're unsure.

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Free Implantation Calculator

This free implantation calculator estimates your likely implantation window and most likely implantation date, using either the first day of your last period or your ovulation date. It also shows your estimated conception date, due date, expected missed period, and earliest pregnancy test date.

Implantation happens when a fertilized egg attaches to the uterine lining, typically 6 to 10 days after conception (ovulation). We estimate ovulation either from your last period and cycle length, or use your ovulation date directly, then add this typical window to estimate when implantation is most likely to occur.

How to Use the Implantation Calculator

Choose whether to calculate from your last period or your ovulation date.
Enter the requested date, plus your cycle and luteal phase length.
Click Calculate Implantation Date.
View your likely implantation window, most likely implantation date, and related pregnancy dates.
Use the Print, Share, Copy, or Download buttons to save your results.

Features

Calculate from either your last period or your ovulation date.
Shows a likely implantation window, not just a single date.
Estimates your conception date, due date, and earliest test date.
Mobile-friendly with print, share, copy, and download options.

Frequently Asked Questions

What is implantation and when does it happen?

Implantation is when a fertilized egg attaches to the lining of the uterus. It typically happens 6 to 10 days after conception, which is roughly the same as ovulation, with 9 days after ovulation being a commonly cited average.

What are the symptoms of implantation?

Some people notice light spotting known as implantation bleeding, mild cramping, or no symptoms at all. Implantation itself is often unnoticeable, and these signs are not a reliable way to confirm pregnancy.

When can I take a pregnancy test after implantation?

The pregnancy hormone hCG needs a few days to build up after implantation before it's detectable. Sensitive tests may pick it up a few days before your missed period, but testing on or after the day your period is due gives the most reliable result.

Can this calculator confirm that implantation has happened?

No. This calculator gives a general estimate for informational purposes only, based on typical timing. It should not be used for legal, paternity, or medical determination purposes. A positive pregnancy test or ultrasound is needed to confirm pregnancy.

Related Calculators

Want to know your conception date instead? Try our conception date calculator. Trying to pinpoint ovulation? Check the ovulation calculator or the fertile window calculator. Already know you're expecting? Use the pregnancy due date calculator.

Last Updated: August 2026