Safe Days Calculator

Use our safe days calculator to avoid the risk of unwanted pregnancy. It's free and easy to use. Also learn how to count safe days after periods.

First day of your last menstrual period (LMP)
Shortest Cycle Length
28 Days
Longest Cycle Length
32 Days
Use it for free on your website: Copy the Embed Code Here

Also Use: Ovulation Calculator, will help you determine your “fertility window”.

Also Use: Due Date Calculator, If you want to know when your precious is coming.

  • Being a responsible, sexually active person is essential if you want to avoid an unplanned pregnancy. If you are not ready to have a baby yet but want to enjoy sexual intercourse, you can do that and still be safe. Safe days are a scientifically tested and proven method of preventing unwanted pregnancies without using any kind of contraception method. 

  • That means no hormones, injections, or drugs in your organism can have various effects on you, including weight gain and extreme mood swings. It is a natural family planning method as it gets, with the lowest risk possible, if properly used. This method will remove any pregnancy scares you might have. 

  • To calculate and plan you're safe days, you first have to know and understand your menstrual cycle. Once you are aware of what is happening in each phase of your cycle, you will be able to precisely calculate the days when it's safe to have sex to prevent conception. 

What are safe days?

Your safe days are those days in the calendar when you have minimal chances to get pregnant if you have sex. This is the "safe window" for those who want to have sex without any kind of protection. During this period, there is not a viable egg present. No egg - no baby. So if you happen to have intercourse, you don't need to be worried. In other words, if you have sex outside your ovulation days, you're good. 

Why is the safe days calculator needed?

The safe sex day calculator tracks the length of your menstrual cycle over multiple months to help you predict your fertile days. Those who choose not to become pregnant can avoid coitus during your fertile period and schedule their sexual activities for when it is safe to not become pregnant or vice versa.

When does ovulation occur?

Ovulation typically occurs approximately 14 days before the start of the next menstrual cycle. To know the exact day is not always possible, though. In the case you have primarily regular periods, you can easily calculate your ovulation days. Simply use the date of your previous menstrual cycle as a starting point. You need to know that an egg can be fertilized by a sperm only four days before and three days after ovulation. To put it simply, days before and post-ovulation are definitely not safe days for sex unless you want to conceive. 

How to count safe days after periods?

To calculate safe days, you first need to understand the different phases of your menstrual cycle. There are three

Safe Period Calculator

  • The follicular phase (pre-ovulation phase)

  • The ovulation phase

  • The luteal phase (post-ovulation)

Different Phase of Menstrual Cycle

The duration of each of the phases varies for women, although it is believed that the average menstrual cycle lasts for 28 days. The first day of the bleeding counts as the first day of the new menstrual cycle.

1. The follicular phase

This phase occurs before ovulation and involves the maturing of the follicles in the ovary. This phase ends with ovulation, and the hormone estradiol is working to help the stimulating hormone (FSH) secretion. 

2. The ovulation phase

A mature ovarian follicle ruptures and discharges a viable egg, ready for fertilization. The ovulation phase is often referred to as the time just before and after ovulation. You are likely to get pregnant if you have unprotected sex on the day you're ovulating. 

3. The luteal phase

This phase is the last one in the menstrual cycle, marked by the creation of the corpus luteum. This phase ends in either pregnancy or the degradation of the corpus luteum, a temporary endocrine structure that helps with estrogen and progestogen production. Those are the hormones your body needs to maintain the endometrium.

Safe days after the period - Safe period chart

A safe period chart is a visual representation of a woman's menstrual cycle, highlighting the estimated days when the chances of pregnancy are considered lower. It helps identify a window of time before and after ovulation, when the likelihood of conception is reduced.

How to count safe days after periods
  • If you want to avoid pregnancy, you will be glad to know that you can calculate safe days after your period. The safe days depend on both the lifespan of the sperm and the egg. Ovulation mainly occurs on the 14th day of the menstrual cycle if it's of an average length of 28 days. This calculation is adjusted to reflect WHO data showing that approximately 80 percent of menstrual cycles range between 26 to 32 days. The ovulation period varies from woman to woman. It can happen anywhere from the 12th to the 19th day of the menstrual cycle. 

  • The sperm can live in your reproductive system for up to five days. That means it is possible to conceive from unprotected sex if you had it five days before ovulation, even though the lifespan of a viable egg is only approximately 24 hours. If it's not fertilized in 24 hours, it will die, and it will be safe for you to have sex. 

How to do the same calculations as on Safe day’s calculator manually?

You can calculate your safe days manually by understanding your menstrual cycle and identifying your fertile window. Here are the steps:

Determine your Menstrual Cycle Length:

You have to first track your menstrual cycles to determine the average length. The menstrual cycle starts from the first day of your period to the day before the next period begins.

Identify the First Day of Fertility:

Subtract 18 days from the total length of your shortest cycle. This is a conservative estimate for the first day of your fertile window.

Identify the Last Day of Fertility:

Subtract 11 days from the total length of your longest cycle. This is a conservative estimate for the last day of your fertile window.

Safe Days Calculation:

The days between the first day of fertility and the last day of fertility are considered potentially fertile. The days outside this window are generally considered safe period.

Limitations of safe days calculator

If on an average your menstrual cycle length is between 26-32 days in last 6 months and there is a variation of <7 days in between your shortest and longest cycle, you may utilize this safe period calculator to avoid pregnancy.

But if your average menstrual period length is <26 days or > 32 days in last 6 months and there is a variation of 8 or more days in between your shortest and longest cycle, you must not use Safe Days calculator.

Also before using this method post child birth you will have to follow a wait time till 6 regular periods. Ovulation period calculator or Safe Days calculator method is not suggested for teenagers and women nearing their menopause.

Finally, keep in mind that these methods don’t promise you 100% safe days for sex. There have been instances when even having sex during your period might be able to make you pregnant. In conclusion, the safest method is always to use protection while having sex.

Situations in which safe period calculator does not work

There are quite a few conditions in which a safe period calculator might nor give accurate results and would fail. Here are 9 such conditions:

  1. Irregular Menstrual Cycles

  2. Recent Childbirth or Breastfeeding

  3. Perimenopause

  4. Recent Use of Hormonal Birth Control

  5. Ovulation at Unexpected Times

  6. Dual Ovulation

  7. Sperm Viability

  8. Reliability of Tracking Methods

  9. Desire for 100% Contraceptive Effectiveness

Safe period calculator really helps

  • In most cases, a cycle calculator will help women determine the safe days of their menstrual cycle. But, you would need to know the date of your periods and your body temperature. Keeping track of your periods for a minimum of six months will help you map out your fertile days. 

  • Important note: If your menstrual cycle is regular 26 do 32 days and the range between your longes and shortest cycle last more than eight days, it is somewhat risky to use the calculator method. Teenagers and women on the verge of menopause should know that the calculator method might not work for them because of their potentially unpredictable cycles. 

Other methods to avoid unwanted pregnancy

If you're not exactly suitable for the safe day calculator method, you can use other fertility awareness methods.

  • tracking your basal body temperature

  • checking cervical mucus

  • using ovulation predictor kits available in drugstores.

Please Note

If you have unprotected sex during the safe period will definitely decrease your chances of getting pregnant. Still, this cannot be taken as a guarantee. Research has shown PUBMED that natural family planning has a 25 percent failure rate. So, if you want to avoid unplanned pregnancy, the safest possible option is to talk to your gynecologist about reliable birth control options for you.


Mayo Clinic

Frequently asked questions