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Safe Days Calendar

Do you want to know how to prevent pregnancy and to know when to conceive? Use our Safe day Calculator to find out this important piece of information

How to Calculate your safe days

Written by Adejumoke Arinola

Fact Checked by Mindsmaking Professionals

24th February, 2025

What are safe days in menstrual cycle

Safe days are the days in a woman's menstrual cycle when the chances of pregnancy are lowest. These usually occur before and after the fertile window (ovulation period).

How do I calculate my safe days

Calculating safe days (or the fertility window) is a natural family planning method used to estimate when a person is least likely to get pregnant. However, this method is not 100% reliable because menstrual cycles can vary.

Steps to Calculate Safe Days:

Track Your Menstrual Cycle
- Record the first day of your period for at least 6 months to determine cycle length.
- The menstrual cycle length is counted from the first day of one period to the first day of the next.
Identify the Fertile Window
- Ovulation usually happens about 14 days before the next period.
- The fertile window includes 5 days before ovulation and 1–2 days after.
Calculate Safe Days
- Safe days are typically:
  - Before the fertile window (early in the cycle): From the first day of menstruation to about Day 7 (for a 28-day cycle).
  - After the fertile window (late in the cycle): From Day 21 until the start of the next period.

Example for a 28-Day Cycle

Day 1-7: Safe (Low chance of pregnancy)
Day 8-19: Fertile window (High chance of pregnancy)
Day 20-28: Safe (Low chance of pregnancy)

Things to Consider:

More accurate when cycles are regular.

Less effective for irregular periods.

Using additional methods (like ovulation tracking, temperature, or cervical mucus) increases accuracy.

If avoiding pregnancy, consider using contraception for better protection.

Using safe days method for pregnancy prevention or planning

If you're using the safe days method for pregnancy prevention or planning, here are some important things to consider:

It’s More Effective for Regular Cycles
Sperm Can Survive for Up to 5-7 Days
Even if you have sex before ovulation, sperm can stay alive inside the body and fertilize an egg when you ovulate. This can make "safe days" less reliable.
Ovulation Can Shift Each Month
Stress, illness, weight changes, and lifestyle factors can cause ovulation to happen earlier or later than expected, making calculations less accurate.
It’s Not 100% Effective
- Failure rate: Around 12-24% in real life.
- More reliable when combined with other tracking methods or barrier methods (like condoms).
The First Few Days of Your Period Are Usually Safe
- The chances of pregnancy are very low during the first 5-7 days of menstruation.
- However, in women with short cycles (<26 days), ovulation may occur earlier, increasing pregnancy risk.
Stress and Health Can Affect Ovulation
- Stress, illness, travel, or weight changes can shift ovulation, making it harder to predict safe days.
- Tracking methods like basal body temperature (BBT) and cervical mucus changes can improve accuracy.
It’s More Reliable When Combined with Other Methods
To increase effectiveness, many people combine safe days with:
Ovulation test strips (detect hormonal changes)
Basal body temperature tracking
Cervical mucus monitoring
Condoms or withdrawal method during the fertile window
Not the Best for Avoiding Pregnancy If You Have Irregular Cycles
If your period comes earlier or later than usual, your ovulation days will shift, making it harder to know your real safe days.
Alternative birth control options:
Birth control pills
IUD (hormonal or copper)
Condoms
Implants
Safe Days Can Be Used to Plan Pregnancy
Instead of avoiding sex on fertile days, you can use this method to conceive by timing sex during your most fertile days.
Digital Apps Can Help Track Safe Days
Apps like Flo, Clue, Natural Cycles, and Ovia help predict ovulation and fertile windows. However, they aren’t 100% accurate and should be combined with other tracking methods.

The other birth control options aside safe days

There are many birth control options, ranging from hormonal methods to natural and permanent solutions. Here’s a breakdown:

Hormonal Methods (Highly Effective)
These release hormones to prevent ovulation and pregnancy.
Birth Control Pills – 91-99% effective
- Taken daily
- Helps with acne & period regulation
Birth Control Patch – 91-99% effective
- Worn on the skin (changed weekly)
- Releases hormones like the pill
Birth Control Shot (Depo-Provera) – 94-99% effective
- Injection every 3 months
- May cause irregular periods at first
Vaginal Ring (NuvaRing) – 91-99% effective
- Inserted into the vagina (changed monthly)
Hormonal IUD (Mirena, Kyleena, Skyla) – 99% effective
- Inserted into the uterus by a doctor
- Lasts 3-8 years, very low maintenance
Barrier Methods (Moderately Effective)
These physically block sperm from reaching the egg.
Condoms – 85-98% effective
- Prevents STDs & pregnancy
- Available for men & women
Diaphragm / Cervical Cap – 71-88% effective
- Small cup inserted into the vagina before sex
- Must be used with spermicide
Spermicide / Gel – 72-86% effective
- Kills sperm, used with other methods
Long-Term / Permanent Methods
For those who want long-term or permanent solutions.
Copper IUD (Paragard) – 99% effective
- Non-hormonal, lasts up to 10 years
- Can cause heavier periods at first
Sterilization (Tubal Ligation / Vasectomy) – 99% effective
- Permanent; surgery required
- Vasectomy is easier & less invasive than tubal ligation
Natural Methods (Less Reliable)
These require careful tracking & discipline.
Fertility Awareness (Safe Days, Temperature, Mucus Tracking) – 76-88% effective
- Works best for those with very regular cycles
- Requires strict tracking
Withdrawal Method (Pulling Out) – 78% effective
- Risky since sperm can be released before ejaculation
Breastfeeding (LAM Method) – 98% effective only if:
- Baby is <6 months
- Mom is exclusively breastfeeding
- Periods haven’t returned

Which One is Best?

It depends on:

Your health

Whether you want kids in the future

Your comfort with hormones

If you need STD protection (only condoms help with this!)

What moms say about safe days

Moms have mixed opinions about using the safe days method for pregnancy prevention or planning. Here’s what many say based on experience:

It Can Work, But Only If Your Cycle is Regular
"I used the safe days method successfully for years, but my cycle is very regular—like clockwork. If your period is unpredictable, I wouldn’t risk it."
Many Moms Got Pregnant Unexpectedly
"I thought I was in my safe window, but surprise! Baby 2 is on the way. Sperm can survive longer than you think."
"Safe days worked for me... until it didn’t. Now I have twins!"
Tracking Can Be Stressful
"I was always second-guessing myself. Did I ovulate earlier this month? Was my calculation correct? I eventually switched to an app to track better."
Some Use It Alongside Other Methods
"I combine it with tracking my basal body temperature and cervical mucus. It takes effort, but it's been effective for me."
"We use condoms during the fertile window and rely on safe days for the rest of the cycle. So far, so good!"
It's More Reliable for Planning a Baby
💡 "I actually used safe days to conceive! I tracked my cycle for months and knew exactly when to try."

Final Thoughts from Moms

Safe days can work if you’re very diligent and have a regular cycle.

Many moms say it’s not foolproof—unexpected pregnancies happen!

If avoiding pregnancy, they recommend combining it with other methods for better security.

Frequently Asked Questions

How accurate is the safe days method?

Click the "Sign Up" button in the top right corner and follow the registration process.

Can I use safe method as birth control?

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Can breastfeeding mom rely on safe days?

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Can I get pregnant on my safe days?