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Birthstone Calculator

Enter the birth month number (1–12) to get the corresponding birthstone.

How it is calculated

This is a lookup, not a formula. You enter the birth month as a number from 1 (January) to 12 (December), and the tool returns the one stone assigned to that month in its list: January garnet, February amethyst, March aquamarine, April diamond, May emerald, June pearl, July ruby, August peridot, September sapphire, October opal, November topaz and December turquoise. A decimal is cut to a whole month (6.9 is read as 6), and numbers outside 1 to 12 give no result. Only the month matters, the day and year are not used. The tool shows a single stone per month. Some months also have traditional or alternative stones in other lists, and the choice varies by country and by jeweller.

Worked example

Someone is born in June and wants a birthstone gift. The month is entered as 6, the sixth month of the year. The tool looks up month 6 in its list and returns Pearl. The same lookup for month 12 would return Turquoise and for month 1 would return Garnet. Which day of June the birthday falls on makes no difference, because the stone depends on the month alone.

Try this example →

Common mistakes

  • Typing the month name or the full date. The field expects the month number, so write 6 for June, not "June" or 15/06.
  • Entering 0 or 13. Months run from 1 to 12, and anything outside that range gives no result.
  • Assuming one global standard. This tool shows one stone per month; other countries and older lists name different or additional stones, so a jeweller may offer a different one.
  • Mixing the birthstone with the zodiac stone. Zodiac signs change around the 20th of the month, while a birthstone follows the calendar month.
  • Entering the month the gift is given in rather than the month the person was born.

About this calculator

This calculator looks up the modern birthstone for any birth month, using the standardized list adopted in 1912 by the American National Retail Jewelers Association (today's Jewelers of America). The list runs from garnet in January through amethyst in February, aquamarine in March, and on to topaz in November and turquoise in December.

The calculator returns one classic stone per month; some months have additional accepted alternatives in newer lists, which it does not show. Jewellers, gift-buyers and anyone shopping for a birthday or push present use this list as the go-to reference for a personally meaningful stone.

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