Celtic tree astrology calculator: find your birth tree
Find your Celtic tree from your birth day and month: Robert Graves's 13 lunar months or Paula Delsol's 21-tree circle, with the real origin of each.
How Celtic tree astrology works
Celtic tree astrology gives each birth date a tree. Two systems coexist: the 13 lunar months of Robert Graves (1948), common in English, and the circle of 21 trees of Paula Delsol (1971), common in French, German and Spanish. Neither goes back to the Celts.
Graves's 13 months
Robert Graves drew 13 months of 28 days from the Ogham alphabet, from birch (24 December to 20 January) to elder (25 November to 22 December). 23 December stays outside the months.
The circle of 21 trees
Sixteen trees return twice a year and poplar three times; four trees hold a single day: oak (21 March), birch (24 June), olive (23 September) and beech (22 December).
Example
For a birth on 15 April, Graves's months give willow (15 April to 12 May); the 21-tree circle gives maple (11–20 April and 14–23 October).
A modern invention
No ancient or medieval source describes a Celtic horoscope. Paula Delsol created the tree circle for Marie Claire in 1971, inspired by Graves. The tool shows the tree, its dates and its botanical genus, with no personality reading or prediction.
Sources and related tools
- Wikipedia (de), "Keltischer Baumkreis", checked on 27 October 2026; Robert Graves, The White Goddess, 1948.
- Your Western sign: zodiac sign and Chinese zodiac. Compare two signs: zodiac love compatibility.
Frequently Asked Questions
Is tree astrology really Celtic?
No. No ancient or medieval source describes it. The 13 tree months come from Robert Graves (1948) and the 21-tree circle was created by Paula Delsol for Marie Claire in 1971.
Which trees cover a single day?
Four trees are tied to the equinoxes and solstices in the 21-tree circle: oak on 21 March, birch on 24 June, olive on 23 September and beech on 22 December.
Why does my tree differ between websites?
English-language sites follow Graves's 13 months, French and German ones the Delsol circle. 15 April gives willow with Graves and maple with Delsol.
What does 23 December give?
With Graves it is the nameless day, outside the 13 months of 28 days. In the 21-tree circle it is apple (23 December to 1 January).
Is this tool really free?
Yes, all tools on Kristools are 100% free and accessible without registration.
Is my data protected?
Yes. All processing is performed directly and securely inside your browser. No personal data is sent to our servers.