What is a logarithm?

In a nutshell

Logarithms are the inverse of exponentiation. When you ask a question like what is the log 2 of X ?, you’re asking 2 raised to what power = X? Let’s consider some examples:

• log₂8
  • 2 raised to what power = 8?
  • Answer: 3 (2^3 = 8)
• log₂16
  • 2 raised to what power = 16?
  • Answer = 4 (2^4 = 16)
• log₂100
  • 2 raised to what power = 100?
  • Answer: 6.6438561898
• log₃8
  • 3 raised to what power = 8?
• log₃20
  • 3 raised to what power = 20?

Related links

• Logarithm calculator