Are you or your partner pregnant? if you know (or can guess) when your baby is due, you can instantly calculate how long to go or which week you are in. The calculation also shows you the trimester you are in too. Simply choose the due date from the calendar dropdowns on the homepage or navigate to the date by clicking on the year, month then day and you’ll get a page with all the countdown answers you need. You can even set a reminder to email you the weeks to go..