Updated: July 2026
What is the Gestation Calculator?
The Pregnancy and Weeks Calculator is every future mother's daily tool. Unlike a common calculator, it acts as a real pregnancy diary. Obstetricians count the gestation period not in "months" (as most people do), but in exact weeks and days.
To do this calculation, we do not use the date on which the baby was conceived, as it is very difficult to be sure of that exact day. Medicine uses LMP (Date of Last Menstruation), as it is the last reliable biological marker in a woman's body.
How to use the Pregnancy Calculator
The usage is pretty straightforward:
- Select, in the date field, the first day of your last menstrual period (LMP).
- The calculator instantly shows you how many weeks and days of pregnancy you are, which trimester you are in and the likely due date.
- Scroll to see the baby's comparative size, likely conception date, and child's estimated star sign.
Baby Size in Fruits 🍎
Monitoring pregnancy just by numbers can be very abstract. What is the real size of a 14 week fetus? That's why our calculator features the beloved Comparative Size feature!
Once you enter the date of your last period, we calculate your exact week and cross-reference it with our botanical database to tell you which seed, fruit or vegetable most closely matches your baby's current size (from a poppy seed to a watermelon!). This is the perfect function to take a screenshot and send it to the family group on WhatsApp.
Baby Sign and Conception Date 🌟
Two other interesting facts that moms love to discover and that our tool calculates instantly:
- The Probable Date of Conception: We do the reverse calculation (LMP + 14 days) to estimate in which week ovulation and conception of the child occurred.
- The Baby's Sign: Based on the Probable Date of Birth (DPP), we cross-reference the date with the Zodiac and inform what the likely astrological sign of the child to be born will be.
How many weeks does a pregnancy last?
The ideal time (full-term pregnancy) is 40 weeks from LMP, totaling around 280 days. But it is perfectly normal for birth to occur between the 37th and 42nd week. DPP is just a medical estimate based on Naegele's Rule, don't be alarmed if the baby wants to come out a few days earlier or later!