Guide to Pregnancy & Family Planning
Whether you're planning for pregnancy or currently pregnant, there are recurring questions: when are the ovulation days? When's the expected due date? And how much water and calories do I need during this period? This guide brings together the calculators related to different stages of pregnancy in a logical order.
Guide steps
Planning for pregnancy? Start here to calculate the expected ovulation day and the highest-chance fertile window, based on your last period date and actual cycle length.
Once pregnancy is confirmed: calculate your expected due date and current gestational week accurately using Naegele's Rule, with important screening test dates.
Your water needs increase during pregnancy — calculate it based on your weight and status (pregnant or breastfeeding) to maintain adequate hydration.
Your calorie needs change during pregnancy — calculate your basic daily need as a reference point to discuss with your doctor the appropriate increase for your situation.
Quick tips
- The highest-chance fertile window is usually 2-3 days before ovulation up to the day of ovulation itself, not after.
- The due date calculated with Naegele's Rule is an estimate (based on a regular 28-day cycle) — your monitoring doctor is a more accurate reference, especially with ultrasound.
- Water and calorie needs increase gradually as pregnancy progresses, not at a fixed rate from start to finish — recalculate each trimester.
- All calculators here are educational, general estimates, and don't replace regular follow-up with an OB-GYN.
Frequently asked questions
My cycle is irregular, will the ovulation calculator work for me?
The calculator assumes a regular cycle to give an estimate — if your cycle is significantly irregular, the result will be less accurate, and it's best to see an OB-GYN for a more precise assessment.
Is the due date calculated here 100% accurate?
No, it's a common medical estimate (40 weeks from the last period) and actual delivery may be about two weeks before or after it and still be considered normal.