Logarithm Calculator | Calculate Log Base 10, Natural Log & Custom Logarithms

Use our free Logarithm Calculator to calculate logarithms with any base. Find common logarithms (log₁₀), natural logarithms (ln), or custom base logarithms instantly with step-by-step formulas.

Logarithm Calculator

Calculate logarithms using any base, including base 10 (common log) and base e (natural logarithm).

Log Result
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Common Log
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Natural Log
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Power Check
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Formula

logb(x) = ln(x) ÷ ln(b)

  • x = Number
  • b = Base
  • b > 0 and b ≠ 1
  • x > 0

Logarithm Calculator

The Logarithm Calculator is an online math tool that calculates logarithms using any base. Whether you need the common logarithm (base 10), natural logarithm (base e), binary logarithm (base 2), or a custom base, this calculator delivers accurate results instantly.

What Is a Logarithm?

A logarithm answers the question:

"To what power must the base be raised to obtain a given number?"

For example:

log₁₀(100) = 2 because 10² = 100.

Logarithm Formula

logb(x) = ln(x) / ln(b)

where:

  • x = Number
  • b = Base
  • b > 0
  • b ≠ 1
  • x > 0

Types of Logarithms

Common Logarithm

Uses base 10 and is written as log(x).

Natural Logarithm

Uses Euler's number (e ≈ 2.718281828) and is written as ln(x).

Binary Logarithm

Uses base 2 and is widely used in computer science.

Custom Base Logarithm

Allows calculations using any valid base greater than zero except 1.

Examples

Example 1

log₁₀(1000)

= 3

because

10³ = 1000

Example 2

log₂(64)

= 6

because

2⁶ = 64

How to Use the Calculator

  1. Enter the number.
  2. Select or enter the logarithm base.
  3. Click Calculate.
  4. View the logarithm, common log, natural log, and verification.

Applications

  • Algebra
  • Calculus
  • Engineering
  • Computer science
  • Machine learning
  • Financial growth models
  • Chemistry (pH calculations)
  • Physics
  • Signal processing
  • Data science

Benefits

  • Supports any logarithm base.
  • Calculates common and natural logs.
  • Instant and accurate results.
  • Easy to use on desktop and mobile.
  • Great for students and professionals.

Frequently Asked Questions

What is a logarithm?

A logarithm is the inverse operation of exponentiation.

What is the difference between log and ln?

log usually refers to base 10, while ln refers to base e.

Can the base be negative?

No. The logarithm base must be greater than zero and cannot equal one.

Can the number be zero?

No. Logarithms are only defined for positive numbers.

Why are logarithms important?

They simplify exponential equations and are used extensively in mathematics, engineering, finance, computer science, and scientific research.

Conclusion

The Logarithm Calculator provides a fast and accurate way to compute logarithms with any base. Whether you're studying mathematics, solving engineering problems, analyzing exponential growth, or working with scientific formulas, this calculator makes logarithmic calculations simple and reliable.

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