American / Japanese Higher Numbers

American Japanese
1   one   1 iti   1  
10   ten   10 juu   10  
100   one hundred   102 hyaku   100  
1 000 one thousand 103 sen   1000  
10 000 ten thousand 104 一万 iti man 1 0000
100 000 one hundred thousand 105 十万 juu man 10 0000
1 000 000 one m-illion 106 百万 hyaku man 100 0000
10 000 000 ten m-illion 107 一千万 is-sen man 1000 0000
100 000 000 one hundred m-illion 108 一億 iti oku 1 0000 0000
1 000 000 000 one b-illion 109 十億 juu oku 10 0000 0000
10 000 000 000 ten b-illion 1010 百億 hyaku oku 100 0000 0000
100 000 000 000 one hundred b-illion 1011 一千億 (is-)sen oku 1000 0000 0000
1 000 000 000 000 one tr-illion 1012 一兆 it chou 1 0000 0000 0000
10 000 000 000 000 ten tr-illion 1013 十兆 jut chou 10 0000 0000 0000
100 000 000 000 000 one hundred tr-illion 1014 百兆 hyaku chou 100 0000 0000 0000
1 000 000 000 000 000 one quadr-illion 1015 千兆 sen chou 1000 0000 0000 0000
10 000 000 000 000 000 ten quadr-illion 1016 一京 ik kei 1 0000 0000 0000 0000
100 000 000 000 000 000 one hundred quadr-illion 1017 十京 juu kei 10 0000 0000 0000 0000
1 000 000 000 000 000 000 one quint-illion 1018 百京 hyak kei 100 0000 0000 0000 0000
10 000 000 000 000 000 000 ten quint-illion 1019 千京 sen kei 1000 0000 0000 0000 0000
100 000 000 000 000 000 000 one hundred quint-illion 1020 一垓 iti gai 1 0000 0000 0000 0000 0000

As can be seen in the chart, the Japanese and American systems for counting higher numbers are based on the same decimal progression - powers of 10. (107 = 1+7 zeros.)

("power" is expressed in Japanese with jou: 乗 -- so, following the pattern, x の x 乗 -- 107 = juu no nana jou = 10の7乗 = ten to the seventh. "squared" (the second power), is often or usually said as ji-jou rather than ni-jou. 22=4, ni o ji-jou suru to yon ni narimasu or ni no ji-jou wa yon desu, two squared is four, the square of two is four.)
However, English counts sets of 1,000 (103 - groups of 3 zeros), while Japanese counts sets of 10,000 (104 - groups of 4 zeros). The English sets are divided into groups of three, 1s, 10s, and 100s, the Japanese, into groups of four, 1s (一 ichi), 10s (十 juu), 100s (百 hyaku), and 1000s (千 sen).

The major set in Japanese is 1,0000, 一万 (ichi man). 1,0000 万, the next set, is 一億 (ichi oku), 108, one hundred million. 1,0000 億 (oku) are 一兆 (itchou), 1012, one trillion. The trillions correspond to the Japanese 兆, except that Japanese continues on up into thousands of 兆, whereas English changes to a quadrillion. The Japanese division above 兆 is 京 (kei), above 京, 垓 (gai).

The major set in English is 1,000, one thousand. 1,000 thousands is a million, 1,000 millions is a billion, etc. The value of the prefix to -illion shows the number of sets of thousands (sets of 3 zeros) beyond the first 1,000. b(i)- (the prefix for 2) indicates a total of 3 sets of 3 zeros 1,000,000,000; tr(i), 4 sets.) Above quadr- (4), the prefixes are quint- (5), sext- (6), sept- (7), oct- (8), non- (9), and dec- (10).

        Basic correspondences:
一万ichi manten thousand
百万hyaku manone million
一億ichi okuone hundred million
十億juu okuone billion
一兆itchouone trillion
千兆sen chouone quadrillion
一京ikkeiten quadrillion
百京hyakkeione quintillion
一垓ichi gaione hundred quintillion