*This calculator uses your last period to calculate your due date.*

Are you expecting a baby? Are you eager to know the estimated due date for your childâ€™s birth? Doubting if you can get a likely date due to the nature of your menstrual cycle? Look no further! The period calculator due date, based on the last menstrual period (LMP), is a tool that helps in determining when a baby is likely to be born. Carefully providing you with the insight you need, including the conception date (depending on your options), the â€˜period calculator due dateâ€™ is definitely an essential aid you need.

## What is the Period Calculator Due Date?

The period calculator due date is a valuable resource that helps to calculate your estimated due date (EDD). It operates on the premise that there are regular and irregular menstrual cycles and seeks to provide accurate results based on your last menstrual period and the formulas that back it up.

Some key benefits that are embodied in this calculator are its ability to accommodate any menstrual cycle, pinpoint accurately the due date based on your LMP, and even provide a connection between you and your unborn child through the knowledge it gives.

However, itâ€™s important to know that while the period calculatorâ€™s due date is built to estimate your due date and give the likely conception date using the LMP formula or Parikhâ€™s formula, the due dates are estimates and not an exact prediction of your babyâ€™s arrival. Only a small percentage of babies are born precisely on their due date. But, most births occur within a two-week window before or after the estimated dates.

This means, although the calculator can precisely predict your due date through the formula it uses, your baby may come earlier or later than the estimated due date. This makes it a gentle reminder that natureâ€™s timing is wonderfully unpredictable.

Nonetheless, letâ€™s check these formulas in the next section.

## Formulas the Period Calculator Due Date Uses You Need to Know

Behind the period calculator due date lies some formulas that help aid your results. These sets of formulas take into consideration your last menstrual period only to predict your due date.

What are these formulas? The formulas used by the calculator are the LMP and Parikhâ€™s formulas.

As weâ€™ve said there are two available options you can use on the calculator. While one accounts for a 28-day menstrual cycle, the other considers the irregularities that occur with menstrual cycles. To account for these, LMP Parikhâ€™s formula comes into play.

### 1. The LMP

The LMP (last menstrual period) operates on the premise that a menstrual cycle typically lasts for 28 days and approximately ovulation occurs on the 14th day of the menstrual cycle. One rule that backs up this belief is Naegeleâ€™s rule. The Naegeleâ€™s rule calculates your due date based on the 28-day menstrual cycle and believes that a pregnancy lasts for 280 days (40 weeks).

This notion is seen in its formula: Due date= LMP â€“ 3 months + 7 months + 1 year.

This means, if your last menstrual period was May 14, 2023, conception occurred on the 28th of May, 2023 and your due date is February 18, 2024.

Weâ€™ve just used the formula by calculating May 14, 2023 â€“ 3 months + 7 months + 1 year.

On the other hand,

### 2. The Parikhâ€™s Formula

This formula considers the irregularities that occur with menstrual cycles. This means it considers the irregular length, time of ovulation, and time of menstrual period. Parikhâ€™s formula believes that a pregnancy lasts for 9 months and inputs that in its formula. Hereâ€™s what it looks like Due date= LMP + 9 months â€“ 21 days + length of the cycle.

Using a sample, if your LMP was January 15, 2023, and your previous cycle length is 35, then your due date is the 31st of October, 2023. This means weâ€™ve just calculated January 15, 2023, + 9 months â€“ 21 days + 35.

Considering both formulas and how they help the calculator in producing your due date estimates, how does the period calculatorâ€™s due date work exactly?

## How Does the Period Calculator Due Date Work?

The calculator works with the data you provide. By inputting the first day of your LMP, the calculator brings out the result. Hereâ€™s a step-by-step guide on how to use the period calculator due date:

### Step 1

Select a method. As you know, there are two methods available on the calculator; the LMP and Parikhâ€™s formula. If you have a regular menstrual cycle, then the LMP method is suitable for you. On the other hand, if you have irregular periods, then go for Parikhâ€™s formula.

### Step 2

Whatever method you choose to go with, your result should be with you by now. If you use the LMP method, you should get your conception date and your due date. Parikhâ€™s formula presents just your due date.

And thatâ€™s it!

## Questions and Answers About Period to Due Date

### 1. How do I calculate my last period from my due date?

Calculating your due date from your last period can be done by either using Naegeleâ€™s rule or Parikhâ€™s formula.

If you have a regular menstrual cycle, then we advise you to go with Naegeleâ€™s rule. However, if not, Parikhâ€™s formula accounts for irregular menstrual cycles.

According to Naegeleâ€™s rule, you subtract 3 months from your last menstrual cycle date, add 7 days, then add a year to get your due date. For Parikhâ€™s formula, Add 9 months to your LMP, subtract 21 days then add the length of your previous cycle.

The calculation might be stressful and thatâ€™s why we encourage you to make use of the period calculator due date available at the top of this article.

### 2. How many weeks am I pregnant from my last period?

To determine how many weeks pregnant you are from your last period, you can use the date of your last menstrual period and count the number of weeks from that date to the current date. Pregnancy is typically calculated from the first day of your last period, so if it has been four weeks since your last period, you would be considered four weeks pregnant.

### 3. How am I 6 weeks pregnant if I conceived 4 weeks ago?

Pregnancy is typically calculated from the first day of your last menstrual period, not from the actual conception date. This is because it is often difficult to pinpoint the exact date of conception. So, if you are 6 weeks pregnant, it means that it has been approximately 6 weeks since the first day of your last period, even though conception likely occurred around 4 weeks ago.

### 4. Is your due date 40 weeks from the first day of your last period?

Yes, in most cases, the due date is estimated to be 40 weeks from the first day of your last menstrual period. This is based on the assumption that ovulation and conception occur around the 14th day of a regular 28-day menstrual cycle. However, itâ€™s essential to remember that only a small percentage of babies are born exactly on their estimated due date.

With the strong sense to provide you with accurate and precise results, the period calculator due date is the tool for you. So, you can plan, prepare, and donâ€™t forget to embrace and cherish every moment of your journey. Remember, while the due date is a stop to pregnancy, the journey itself is likewise important.

### Sources used for this article:

- https://reference.medscape.com/calculator/240/due-date-by-lmp
- https://www.parents.com/pregnancy/giving-birth/labor-and-delivery/the-truth-about-due-dates/
- https://www.hopkinsmedicine.org/health/wellness-and-prevention/calculating-a-due-date
- https://www.morulaivf.co.id/en/blog/how-to-calculate-the-estimated-due-date-of-birth-hpl-accurately-learn-the-formula/