Conception date method
Chinese Conception Calendar
If you know your conception date, you have the exact input this chart was built around, with no estimating and no working backwards. Enter it below with your date of birth.
Dates from 1900-01-31 to 2101-01-28 are supported. Nothing you type leaves your browser The whole calculation runs on this page.
Conception date is the input, not a substitute for one
The other ways into this chart (a due date, a last period date) all exist to estimate one thing: when conception happened. If you already know it, you skip that estimate and its error.
You may know it directly if you:
- tracked ovulation with tests, temperature or an app;
- had IVF or IUI, where the date is in your clinic notes;
- conceived in a cycle where you know exactly when you ovulated.
From conception date to a chart column
The chart’s twelve columns are lunar months, which begin at new moons and run 29 or 30 days. They never line up with January to December. Lunar month 1 starts on Chinese New Year, which in 2026 falls on 17 February 2026.
Find your conception date in the table below to read off its lunar month.
| Lunar month | Conceived between | Length |
|---|---|---|
| 1 | 17 Feb – 18 Mar | 30 days |
| 2 | 19 Mar – 16 Apr | 29 days |
| 3 | 17 Apr – 16 May | 30 days |
| 4 | 17 May – 14 Jun | 29 days |
| 5 | 15 Jun – 13 Jul | 29 days |
| 6 | 14 Jul – 12 Aug | 30 days |
| 7 | 13 Aug – 10 Sept | 29 days |
| 8 | 11 Sept – 9 Oct | 29 days |
| 9 | 10 Oct – 8 Nov | 30 days |
| 10 | 9 Nov – 8 Dec | 30 days |
| 11 | 9 Dec – 7 Jan | 30 days |
| 12 | 8 Jan – 5 Feb | 29 days |
2026 is an ordinary lunar year with twelve months, so there is no intercalary month to complicate the lookup. Other years do have one, and the calculator handles those automatically and flags it when your date falls inside one.
Worked example
Mother born 15 June 1995, conceived 10 March 2026:
- 10 March 2026 falls in lunar month 1 of 2026.
- Her lunar age at that date is 32. Note this is already higher than her Gregorian age, because Chinese New Year 2026 had passed.
- Chart row 32, column 1 → Boy.
Row 32 in full shows what that age predicts across all twelve months.
The part that trips people up
The lunar age is worked out at the moment of conception, not today and not at the birth. And it changes on Chinese New Year rather than on the mother’s birthday, so two conception dates a day apart, either side of New Year, land on different rows of the chart entirely.
This is where most other calculators go wrong, and it is not a small error: neighbouring rows disagree in a large share of their twelve months. Our conversion is tested against an independent reference for every date from 1900 onward, which you can read more about on the about page.
Conception date questions
What is the Chinese conception calendar?
It is the same traditional chart as the Chinese gender calendar, named after the input it actually uses: the lunar month you conceived in, paired with the mother’s lunar age at that moment.
How do I know my conception date?
If you tracked ovulation, used an ovulation test, or had IVF, you may know it directly. Otherwise it is estimated, usually about 14 days after the first day of your last period, or 266 days before your due date.
Does the conception date mean the day we had sex?
Not necessarily. Sperm can survive several days, so conception is the day the egg was actually fertilised, which may be a day or more later. For this chart the difference only matters if it moves you across a lunar month boundary.
Which lunar month does my conception date fall in?
That depends on the year, because lunar months begin at new moons and shift against the Western calendar. The table on this page lists every lunar month of 2026 with its exact Gregorian dates, and the calculator works it out automatically for any year.