Pi Digit Explorer

Positions are counted after the decimal point, so the whole part 3 is not numbered at all: in π = 3.14159265… position 1 is 1, position 2 is 4 and position 5 is 9. The 100th digit of pi is 9.

The answer is read from a stored sequence of the first 1,000,000,000 decimal digits of pi, so any position from 1 to 1 billion is a direct lookup rather than a fresh computation. That is also why the form refuses positions beyond the billionth digit.

Pi is irrational and transcendental, so its decimal expansion never ends and never becomes periodic — but it is not random either, since every digit is uniquely determined. Whether pi is "normal", meaning each digit appears one time in ten in the long run, is still an open problem, although in the first billion digits each of the ten digits occurs very close to 10% of the time.