From conception month to birth month
A pregnancy lasts about 266 days from conception, so each conception month leads to due dates about nine months later. Because 266 days is a little less than nine calendar months, conceptions early in a month lead to due dates late in the eighth month after, and later conceptions to the ninth.
| Conception month | Due dates fall in | Conception month | Due dates fall in |
|---|---|---|---|
| January | September – October | July | March – April |
| February | October – November | August | April – May |
| March | November – December | September | May – June |
| April | December – January | October | June – July |
| May | January – February | November | July – August |
| June | February – March | December | August – September |
Each month also has its own page with every day’s due date — for example If I Get Pregnant in May, When Am I Due?
Day-by-day chart
Choose a month in the tool above to see each possible conception day, the matching pregnancy start date (about 14 days earlier, which is how pregnancy weeks are counted) and the due date.
A note on conception dates
Most people don’t know their exact conception day. It usually happens within a day of ovulation, which may be up to five days after sex. If you know the first day of your last period, the Due Date Calculator is the standard method; if you know an exact ovulation date, use the Due Date Calculator by Conception.