Saiyan God is the most powerful Super Saiyan transformation in the entire molecular intergalactic universe. It has a power level of (see below). It is just more powerful than the god of the entire universe, and who created it (it is unknown who, and no it is not the Christian god). Vegeta is the first to achieve it, as he cycles power from the gods realm, and is over 550 quadrillion times more powerful than every Supreme Kai together times 997 million. The form rivals the gods of death and destruction.
In the form, you have black fur, your muscles are wider than an average kitchen table. Your veins are pulsating blood red, your voice deepens very low and your hair sticks up, completely black and standing in all directions, so pointy it can destroy a Grand Kai. Your aura is black with black lightning. Your power is enough to destroy the entire galaxy with a simple ki blast.
Your are everything, your enemies are nothing.
LOGICAL BASIS BASED ON THE THEORIES. HIS POWER LEVEL (DEFINED):
A Googol is 100 zeroes: 0000000000000000000000000000000000000000000000000000000000000000000000 000000000000000000000000000000.
A Googolplex is a Googol of zeroes. So imagine the number above^, times itself of that many zeroes.
A Megaplex on the Kuzon Scale: Googolplex times Googolplex. To understand what a googolplex is, one first has to understand what a googol is. A googol is 10 to the 100th power, or 1 followed by 100 zeros. A googolplex, then, is 1 followed by a googol of zeros, or 1 followed by 10 to the 100th zeros. If there were a zero for every subatomic particle in the known universe, one would still not have enough zeros.
>For another example of the suffix "-plex", say you have the number 3. Then a 3-plex is 1 followed by 3 zeros. Similarly a 6-plex is 1 million. A googol is a hundredplex, 1 followed by 100 zeros. So finally, a googolplex is a hundredplexplex.
So that is a LOT of zeroes.
BUT, it is times that number^ times an OMEGAPLEX.
An Omegaplex is a Megaplex to the Megaplexth power times a Megaplex. Remember a Megaplex is a lot of zeroes, so an Omegaplex is pretty big. You would have to fill every corner in the entire subatomic universe up over a Googol times to even reach a third of how many zeroes are in an Omegaplex. Or, about a Googolplex years (about the age of the universe times a Googol).
But, that is not even half of how powerful a Saiyan God is.
Above an Omegaplex, is an KYNTHRAPLEX. On an logical basis of the rictor scale and Kuzon scale, a Kynthraplex is an Omegaplex times an Omegaplex to the Omegaplexth power times an Omegaplex times a thousand. So it is a big number. Compared to the x function.
So that is enough zeroes to cover the entire earth, about Omegaplex times/Megaplex.
Therefore, Saiyan God is powerful enough to destroy Frieza in a megaplexth of a nonosecond (a googolth of a second).