HealthCalc Hub

Due date for conception in March

Find your due date by month. This page covers a conception in March from day 1 to day 31 and shows where each date lands.

Pick a date to see your due date.

This calculator gives general information only. It is not medical advice. Talk to a doctor or other qualified health professional about your own health.

How it works

The page adds 266 days to your conception date. That is 38 weeks. On this page day 15 maps to 6 December.

Worked example

Use 15 March as the day of conception. Add 266 days for a due date of 6 December. The range for the month is 22 November to 22 December. This example uses a 365-day year.

Estimated due date for each day of March, counting 266 days from the day of conception. The table uses a 365-day year.

Date of conceptionDue date
1 March22 November
2 March23 November
3 March24 November
4 March25 November
5 March26 November
6 March27 November
7 March28 November
8 March29 November
9 March30 November
10 March1 December
11 March2 December
12 March3 December
13 March4 December
14 March5 December
15 March6 December
16 March7 December
17 March8 December
18 March9 December
19 March10 December
20 March11 December
21 March12 December
22 March13 December
23 March14 December
24 March15 December
25 March16 December
26 March17 December
27 March18 December
28 March19 December
29 March20 December
30 March21 December
31 March22 December

Common questions

What if I only know the month?

Use the middle of the month. The due date then falls in the middle of the window. Day 15 of March maps to 6 December.

How many weeks is the gap?

Divide the days by 7 to get weeks. From day 1 of March to 22 November is 266 days, which is 38 weeks.

What if my cycle is not regular?

When cycles are irregular, an ultrasound can date a pregnancy more reliably than a calendar. A date of 15 March would then give 6 December only as a first guess.

Does the year change the due date?

Only if the span includes 29 February, which moves the date one day earlier. The span from 15 March does not cross February. A leap year changes nothing for 6 December.

How reliable is a due date worked out by month?

It is an estimate, and births spread across the weeks around it. A conception on day 15 of March gives 6 December, with arrivals spread across the weeks around that date.