It has been out there since 1998, it is the one everyone copied for years then others created flash versions and database versions.

However none of the other calculators have supporting videos, or documentation of related information. I like this one the best but you can find lots of others.

If you use "gematria calculator" or 666 calculator you find lots more using the progression of 6 values. This is not something that is new it is just not well known because it deals with numbers and of course which most Christians are afraid to look at let alone calculate, even though the Bible tells them to do it.