HealthCalc Hub

Due date for conception in May

Enter your conception date to get a due date. This page is set up for May. The table below covers each day from day 1 to day 31.

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. For May, day 1 maps to 22 January.

Worked example

Say the day of conception is 15 May. Add 266 days to reach 5 February. Day 1 of May gives 22 January and day 31 gives 21 February. This example uses a 365-day year.

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

Date of conceptionDue date
1 May22 January
2 May23 January
3 May24 January
4 May25 January
5 May26 January
6 May27 January
7 May28 January
8 May29 January
9 May30 January
10 May31 January
11 May1 February
12 May2 February
13 May3 February
14 May4 February
15 May5 February
16 May6 February
17 May7 February
18 May8 February
19 May9 February
20 May10 February
21 May11 February
22 May12 February
23 May13 February
24 May14 February
25 May15 February
26 May16 February
27 May17 February
28 May18 February
29 May19 February
30 May20 February
31 May21 February

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 May maps to 5 February.

How many weeks is the gap?

Divide the days by 7 to get weeks. From day 1 of May to 22 January 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 May would then give 5 February 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 May does not cross February. A leap year changes nothing for 5 February.

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 May gives 5 February, with arrivals spread across the weeks around that date.