Mainland China, Hong Kong, Taiwan and the Chinese diaspora
Lucky 6 8 9 · avoid 4
Germany, Austria and German-speaking Switzerland
Lucky 3 4 7 · avoid 13
India, Nepal and the South Asian diaspora
Lucky 108 9 7 · avoid 8
Italy, and Italian communities abroad
Lucky 3 7 13 · avoid 17
Japan
Lucky 3 7 8 · avoid 4 9
Israel and Jewish communities worldwide
Lucky 18 7 13 · avoid 2
South and North Korea, and Korean communities abroad
Lucky 3 7 · avoid 4
Russia, Ukraine, Belarus and much of the former Soviet space
Lucky 3 7 · avoid 2 13
Thailand
Lucky 9 5 · avoid 6 4
Britain, Ireland, North America and most of western Europe
Lucky 7 3 12 · avoid 13
Almost every number superstition on this page traces back to something concrete: a word the number sounds like, a letter it stands for, or a count that recurs in a sacred text.
That is the useful thing to know about number luck, and it is the part most listicles skip. Once you know that Mandarin 八 bā sits a tone away from 發 fā, to prosper, the price of a Hong Kong licence plate stops being mysterious. Once you know Hebrew letters double as numerals, 18 turning up on wedding cheques makes immediate sense. The belief is not arbitrary; it is downstream of a language.
It also means the beliefs do not transfer. Four is dangerous in Seoul and harmless in Stockholm, because the Korean word for four collides with the word for death and the Swedish one collides with nothing. Where a superstition has crossed a border, it has usually travelled with people, trade or a film rather than arriving on its own.
The strongest driver in East Asia. Mandarin has few syllables and many characters, so numbers collide with ordinary words: 八 bā with 發 fā, to prosper, and 四 sì with 死 sǐ, death. Japanese and Korean inherited the same collisions through Chinese loanwords.
Hebrew and Greek letters double as numerals, so any word has a number and any number can be read back as a word. That is how 18 became the Jewish number for life: חי, chai, is ח (8) plus י (10).
Numbers that recur in a religious text pick up weight from repetition. Seven runs through Genesis and the week; 108 runs through Hindu and Buddhist practice, from mala beads to temple steps.
Sometimes it is the glyph, not the sound. Japanese reads 八 as auspicious because the strokes widen towards the bottom, a shape called suehirogari, spreading out towards the end.
Italy's unlucky 17 is a Roman-numeral trick: XVII rearranges to VIXI, I have lived, which on a tombstone means the writer is dead. No sound is involved, only the letters.
Traditions travel, usually with trade or with a film. Friday the 13th spread out of the English-speaking world during the twentieth century and now turns up in places with no local thirteen tradition of their own, sitting alongside the older numbers rather than replacing them.
Treated as lucky
Nothing about an outcome. A raffle drawn with a 4 in it is exactly as likely to come up as one with an 8, and no lottery has ever noticed which digits people prefer. What does change is behaviour, and that part leaves a paper trail: apartments priced differently by floor number, hospital rooms renumbered, phone numbers auctioned, wedding dates clustered on a single auspicious day.
That is why these pages cite sources. A tradition described with a real example, a named institution and a date is worth reading. The same tradition described with "many people believe" is worth nothing, and it is what most of the internet offers on this subject.
A number attached to a whole language is a different thing from a number attached to one person. If you want the second kind, the Life Path calculator derives one from a birth date and the zodiac pages derive one from a sign, both with the arithmetic shown rather than asserted.
There is no single answer, but 7 comes closest to being universal: it is treated positively across Western, Jewish, Japanese, Korean and much of Islamic tradition. 8 is more localised and far more consequential where it holds, because in Chinese it has a specific prosperity homophone behind it rather than a general good feeling.
Because the word for four sounds like the word for death in all three languages, through the shared Chinese root: sì and sǐ in Mandarin, shi and shi in Japanese, sa and sa in Korean. The avoidance is linguistic, not religious, which is why it does not appear in cultures whose word for four sounds like nothing in particular.
No. No number changes the probability of anything, and every page here says so. What these beliefs do change is human behaviour, which is measurable: prices, floor plans, phone-number auctions, the dates people choose to marry on.
13 is the clearest case. Western tradition avoids it, Italy treats it as a winning number, and Jewish tradition attaches it to adulthood and to the Thirteen Attributes of Mercy. 4 splits the same way: unlucky across East Asia, lucky in Germany through the four-leaf clover.
The behaviour is. Antipov and Pokryshevskaya, publishing in Judgment and Decision Making in 2015, looked at new-build blocks in Saint Petersburg with identical floor plans and found 54.9% of thirteenth-floor flats sold against 64.8% on the twelfth and 61.8% on the fourteenth. Seventh-floor flats led the building at 68.6%. The luck is not measurable. The market for it is.