About Us & Medical Methodology
Hasibatul Hamal is created to provide simple tools that help you understand dates and stages related to pregnancy, menstrual cycles, ovulation, and pregnancy testing. Our aim is to turn calculations that may seem complicated into clear, easy-to-read results while explaining that these results are estimates and do not constitute a medical diagnosis.
What do our tools cover?
- The Pregnancy Calculator estimates gestational age, pregnancy week, month and expected due date.
- The Ovulation and Fertile Days Calculator estimates ovulation timing and the fertile window.
- The Period Calculator estimates upcoming menstrual dates and cycle patterns.
- The Pregnancy Test & hCG Calculator helps with test timing, numerical hCG results and comparison of two results.
- The Pregnancy Calendar and Diary follows your pregnancy week by week and lets you record your notes along the way.
Each tool uses a different methodology because pregnancy dating, ovulation prediction, menstrual tracking, hCG interpretation and week-by-week journaling are different tasks.
How are the calculations made?
Pregnancy Calculator
When pregnancy is dated from the last menstrual period, conventional gestational dating begins on the first day of the last menstrual period. About 280 days, or 40 weeks, from that date is commonly used to estimate a due date.
This method cannot account perfectly for every cycle or ovulation pattern, so other dating information may sometimes be more appropriate.
ACOG states that first-trimester ultrasound is the most accurate ultrasound method for establishing or confirming gestational age. For pregnancies resulting from assisted reproductive technology, embryo age and transfer date should be used to establish the estimated due date.
A general calculator should therefore not override clinically established pregnancy dating.
Ovulation and fertile days
Ovulation calculations use menstrual-cycle information to estimate when ovulation may occur. They cannot determine the exact day an egg is released.
ASRM defines the fertile window for counselling purposes as the six-day interval ending on ovulation day and notes that its timing can vary considerably even among people with generally regular cycles.
For this reason, our tools describe ovulation and fertility dates as expected or estimated, not guaranteed.
Calendar prediction alone should also not be treated as a standalone contraceptive method.
Period Calculator
A menstrual cycle is measured from the first day of one period to the first day of the next.
A cycle does not need to last exactly 28 days. NHS guidance notes that regular adult cycles can commonly range from about 21 to 35 days.
When cycle lengths vary, using several recent cycles and presenting an expected range is more transparent than pretending that one exact future date is known.
We also distinguish between cycle length, which measures the interval between period starts, and bleeding duration, which measures how long menstrual bleeding lasts.
Pregnancy tests and hCG
Pregnancy tests detect human chorionic gonadotropin (hCG) in urine or blood. Blood testing can be qualitative, indicating whether hCG is present, or quantitative, measuring its concentration numerically.
A test-timing calculator can estimate when testing may be useful, but it cannot guarantee that a test will be positive on a particular day.
A single quantitative hCG value should not be used by our calculator to declare that a pregnancy is healthy or unhealthy, diagnose miscarriage or ectopic pregnancy, or determine exact gestational age.
When two results are entered, the tool may calculate their percentage change and time interval to describe the trend. Clinical interpretation may still require additional hCG tests, symptoms, examination or ultrasound.
Hijri and Gregorian dates
Where both calendars are supported, changing between Hijri and Gregorian dates changes how the date is displayed; it does not change the biological basis of the pregnancy, cycle or ovulation calculation.
Date-conversion methods can themselves introduce small differences, so calendar-based outputs should still be treated as estimates.
How do we deal with uncertainty?
All health calculators have limitations.
That is why we use words like “expected” and “estimated” when the date or result cannot be known with certainty.
We do not use greater numerical precision than the input data allows.
Results may vary due to:
What can our calculators not do?
If a healthcare professional has established pregnancy dating or a treatment plan using appropriate clinical information, that assessment should take priority over a general online estimate.
Our tools cannot:
When should you seek medical care?
Do not use an online calculator to delay medical assessment when you have concerning symptoms.
Seek appropriate medical care for symptoms such as severe pain, unusual or heavy bleeding, dizziness or fainting when pregnancy is possible, persistent significant changes in menstrual patterns, or any symptom that causes concern.
Why do these tools exist?
Our goal is simple: provide a result that is easy to understand while making its limitations equally clear.
A useful health calculator should do more than produce a number. It should explain what the result represents, how it was estimated, and when that result is not enough to make a health decision.
Medical disclaimer: All calculators and content on this website are provided for general information and education. They do not provide diagnosis or treatment and do not replace professional medical advice or care.
Have a question or feedback?
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