# TI 84 Calculator: Calculate Log Base X of Y

**Problem: **I have a graphing calculator and I want to calculate the log with base X of the number Y. For instance, maybe I want to calculate the log with base 4 of 16.

**Solution: **According to MathBits, in order to do this, all we have to do is use the Change of Base formula:

Log of base X of Y = log(our number)/log(base) = log(Y)/log(X)

*As long as the bases are the same.*