Pregnancy Due Date: Your Questions Answered
These are the questions people ask most often about pregnancy due date. Each answer is short; follow the links for the full detail.
What does a pregnancy due date calculation tell me?
Estimates your due date using Naegele's rule.
What is the formula?
Due date = first day of last period + 280 days.
What do I need to enter?
First day of last period.
Is this a medical assessment?
No. These are general estimates. Speak to a doctor or polyclinic for advice about your health.
Can you show an example?
For example, with these inputs:
- First day of last period: 1 Mar 2026
the calculator returns:
- Estimated due date: 6 Dec 2026
- End of first trimester: 6 Jun 2026
Any tips?
- Singapore's heat and humidity raise fluid needs, especially when exercising outdoors.
- Measure at the same time of day, ideally in the morning, for consistent readings.
- See a healthcare professional before big changes to diet or exercise, especially if you have a medical condition.
Background
Energy needs depend on age, sex, size and activity. Formulas such as Mifflin-St Jeor estimate resting needs, and an activity multiplier turns that into daily needs. Real requirements vary by a few hundred calories, so adjust based on how your weight changes over several weeks.
Singapore's tropical climate means you lose more fluid through sweat, even when you are not exercising. Thirst, urine colour and how you feel are good guides, and needs rise during outdoor activity or heat waves.
Research has shown that Asians tend to develop conditions such as type 2 diabetes and heart disease at lower body weights than Europeans. That is why the Health Promotion Board recommends lower BMI cut-offs for Singaporeans, with 23 marking the start of moderate risk.
Related calculations
- Ideal Weight Calculator: Gives an ideal-weight estimate and the healthy weight range for your height.
- Daily Water Intake Calculator: A rough guide to daily fluid needs in Singapore's hot, humid climate.
- Calorie Deficit Calculator: Sets a daily calorie target for steady weight loss.
- Ovulation Calculator: Estimates ovulation and the fertile window.
Try it yourself with the Pregnancy Due Date Calculator.
Run your own numbers: Pregnancy Due Date Calculator