Random Birthday Generator
Set the years you want and press the button. You get a date of birth, the day of the week it fell on, and the age that makes today. Every day in the range is equally likely, and 29 February only comes up in years that had one. Handy for test data, characters and forms.
Set a range and press the button for a birthday.
The twelve months, with the traditional birthstone and flower
| Month | Birthstone | Birth flower | Days |
|---|---|---|---|
| January | Garnet | Carnation | 31 |
| February | Amethyst | Violet | 28, or 29 in a leap year |
| March | Aquamarine | Daffodil | 31 |
| April | Diamond | Daisy | 30 |
| May | Emerald | Lily of the valley | 31 |
| June | Pearl | Rose | 30 |
| July | Ruby | Larkspur | 31 |
| August | Peridot | Gladiolus | 31 |
| September | Sapphire | Aster | 30 |
| October | Opal | Marigold | 31 |
| November | Topaz | Chrysanthemum | 30 |
| December | Turquoise | Narcissus | 31 |
Birthstones follow the modern list adopted by American jewellers in 1912 and revised since; older and regional lists differ, and several months have alternatives — June also has alexandrite and moonstone, December also has tanzanite and zircon. Birth flowers vary even more by country. Both are traditions, not facts about people.
How this list was built
Every day in the range is equally likely, which most birthday generators get wrong. Picking a month and then a day between 1 and 31 produces 31 February and over-weights short months. This page counts the actual days between your two dates and picks one, so the distribution is flat and no impossible date can appear.
The age is worked out properly, not by subtracting years. Someone born on 20 September 1990 is 35 today if today is before 20 September and 36 after it. The generator checks the month and day, not just the year.
The default range is 1940 to 2015 for a reason. It covers the adults and older children most test data and fiction need. Widen it for anything else — the boxes take any dates your browser accepts.
Birthstones and birth flowers are traditions, and the table says so. They differ by country and by era, and a page that presents one list as the truth is overstating it. The modern American jewellers' list is the one most people mean, so that is the one shown, with the main alternatives named in the note.
Common questions
Is every birthday equally likely?
Yes, every day in the range you set. That is not true of real births — more people are born in September than in February — but for test data and fiction a flat distribution is what you want.
Can I generate a birthday for someone a specific age?
Set the range to the same day in two years. For someone who is exactly 30 to 31 today, set From to today's date 31 years ago and To to today's date 30 years ago.
Why does the leap day only appear sometimes?
Because 29 February only exists in leap years, and the generator picks from days that actually happened. A generator that can produce 29 February 2023 is broken.
Are the birthstones official?
There is no official list — they are a jewellery-trade tradition, and the modern list dates from 1912 with later additions. Several months have two or three accepted stones, which the note under the table sets out.
Other generators
- Random name generator — A real first name, filtered by gender and where it comes from
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