Actually yaar, just count from the start date of your last period. There are so many free pregnancy calculator websites online where you just put that date and they give you the exact week and day. It's super simple!
Look, you don't need any complex math. Just note down the date your last period started. Doctors count the weeks and days from that date, not from the date you missed your period or had sex.
You calculate it starting from the first day of your Last Menstrual Period (LMP), even though you actually conceived later. Don't worry too much about the exact days, your doctor will give you a clear Estimate Due Date during your first scan. It's an exciting journey, enjoy it!
In our house, my MIL and mummy told me to calculate from the very first day of my last period. That is how doctors count it too, which was surprising to me back then! But it's best to confirm it with a dating scan at the hospital.
Haha, trying to do pregnancy math is a whole different level of science! Just count from the first day of your last period, but honestly, let the ultrasound machine do the hard work during your first doctor visit. No need to burn your brain cells over it!