Logarithm Calculator

Calculate logarithm of a number to any base:

log
	2 e 10
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Result:
Description:

* Use e for scientific notation. E.g: 5e3, 4e-8, 1.45e12

When:

b ^y = x

Then the base b logarithm of a number x:

log_b x = y

Anti-logarithm calculator

In order to calculate log^-1(y) on the calculator, enter the base b (10 is the default value, enter e for e constant), enter the logarithm value y and press the = or calculate button:

settingsCalculate clearReset
Result:

When

y = log_b x

The anti logarithm (or inverse logarithm) is calculated by raising the base b to the logarithm y:

x = log_b^-1(y) = b ^y

Logarithm rules

Logarithm product rule

log_b(x × y) = log_b(x) + log_b(y)

Logarithm quotient rule

log_b(x / y) = log_b(x) - log_b(y)

Logarithm power rule

log_b(x ^y) = y × log_b(x)

Logarithm base switch rule

log_b(c) = 1 / log_c(b)

Logarithm base change rule

log_b(x) = log_c(x) / log_c(b)

 

 

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See also

• Natural logarithm calculator
• Exponents calculator
• Antilog calculator