Log Base N Calculator

Calculate logarithms with any custom base, including step-by-step solutions

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Expression:

log()

log()

Step-by-Step Solution

Logarithm Properties Reference

Property Formula

Common Logarithm Bases

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About Log Base N Calculator

What is Log Base N?

Log Base N (written as log_n(x)) is the logarithm of a number x to base n. It answers the question: "To what power must n be raised to get x?" If log_n(x) = y, then n^y = x.

How to Use This Calculator

  1. Enter the Number (x): Input the positive number you want to find the logarithm of
  2. Enter the Base (n): Input any positive base (except 1)
  3. View Instant Results: See the result with step-by-step explanation
  4. Compare Bases: View the same number's logarithm in common bases (2, e, 10)

The Formula

Log Base N Formula: log_n(x) = ln(x) / ln(n) = log₁₀(x) / log₁₀(n)

This is known as the Change of Base Formula, which allows calculating logarithms of any base using natural or common logarithms.

Common Logarithm Bases

Binary Logarithm (Base 2)

  • Used in computer science, information theory
  • log₂(8) = 3 because 2³ = 8

Natural Logarithm (Base e ≈ 2.71828)

  • Used in calculus, physics, engineering
  • ln(e) = 1 because e¹ = e

Common Logarithm (Base 10)

  • Used in scientific notation, pH scale, decibels
  • log₁₀(100) = 2 because 10² = 100

Logarithm Properties

Product Rule

log_n(ab) = log_n(a) + log_n(b)

Quotient Rule

log_n(a/b) = log_n(a) - log_n(b)

Power Rule

log_n(a^k) = k × log_n(a)

Change of Base

log_a(x) = log_b(x) / log_b(a)

Frequently Asked Questions

What is a valid base for logarithms?

The base must be positive and not equal to 1. Common bases include 2, e (≈2.718), 10, and any other positive number.

Why can't the base be 1?

If the base were 1, then 1^y = 1 for any y, meaning 1^y can never equal any number other than 1. This makes the logarithm undefined for x ≠ 1.

Why can't x be negative or zero?

Logarithms are only defined for positive real numbers. log_n(0) approaches negative infinity, and log_n(negative) requires complex numbers.

How do I convert between logarithm bases?

Use the change of base formula: log_a(x) = log_b(x) / log_b(a). This lets you calculate any logarithm using a calculator that only has ln or log₁₀.

Real-World Applications

  • Earthquake Magnitude: The Richter scale uses log₁₀
  • Sound Intensity: Decibels use log₁₀
  • pH Scale: Measures acidity using -log₁₀
  • Algorithm Complexity: O(log n) in computer science
  • Compound Interest: Time calculations use natural log

Note: This calculator provides accurate results for any positive base (except 1) and any positive number x.