Logarithm Calculator
Compute log₁₀, natural log (ln), and log of any base. Or do the reverse: find the antilog from a given logarithm.
How to use
- 1
Pick which logarithm you want: common (log₁₀), natural (ln), arbitrary base, or antilog.
- 2
Enter x. For arbitrary base, also enter the base.
- 3
Negative or zero x is undefined for log functions — use antilog instead.
Frequently asked questions
log without a subscript usually means log base 10 (the common logarithm) in finance, engineering, and most calculators. ln is the natural logarithm with base e (≈ 2.71828), used in calculus, statistics, and continuously-compounded growth. They're related: log₁₀(x) = ln(x) / ln(10) ≈ ln(x) / 2.303.
There's no real number you can raise a positive base to and get a negative result. For example, 10^x is always positive — there's no x where 10^x = −5. Log of negative numbers is defined in complex analysis, but this calculator stays in the real numbers.
Antilog is the inverse of log. If log₁₀(x) = y, then antilog₁₀(y) = 10^y = x. It's useful when you have a logarithm and need the original value — common in chemistry (pH), acoustics (decibels), and seismology (Richter scale).
No. Base 0 is undefined (0^x = 0 for any positive x, so log₀ has no meaningful inverse). Base 1 fails because 1 raised to any power is 1 — there's no unique exponent.
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Source: Standard logarithm definitions · Last verified 2026-06. This tool provides estimates only and is not legal, tax or financial advice. Always verify your specific situation with the relevant UAE authority or a licensed advisor before taking action.