– tiykarı $a$ ($a>0$ hám $a\neq 1$) bolǵan logarifmnen tiykarı $b$ ($b>0$ hám $b\neq 1$) bolǵan logarifmge ótiw moduli $\dfrac{1}{\log_{a}b}$ kóbeytiwshige teń, yaǵnıy $\log_{b}N=\dfrac{\log_{a}N}{\log_{a}b}=M\log_{a}N$, bunda $M=\dfrac{1}{\log_{a}b}$. Mısal: onlıq logarifmnen natural logarifmge ótkende $M=2,30258...,$ al natural logarifmnen onlıq logarifmge ótkende $M=0,43429...$.