What is an antilog?
The antilog undoes a logarithm: if y = log₁₀(x), then x = 10^y.
Log and Antilog Calculator
Find log₁₀(x), ln(x), or reverse with antilog 10^x and e^x.
Choose log or antilog
Select the operation and enter a positive value for logs (any real for antilogs).
About this calculator
How to use Log and Antilog Calculator, plus the formulas and logic behind the results.
Tool description
Logarithms undo exponential growth. Common log uses base 10; natural log uses base e ≈ 2.71828. Antilogs reverse those maps.
How to use
- Select log₁₀, ln, 10^x, or e^x.
- Enter x (must be positive for logarithms).
- Select Calculate to view the result.
- Use Clear to restore the sample value.
Formulas & reference
log₁₀(x) = ln(x) / ln(10)ln(x) = log_e(x)Antilog₁₀(x) = 10^xAntilog_e(x) = e^x
Quick checks
- log₁₀(100) = 2
- ln(e) = 1
- 10^2 = 100
- e^0 = 1
Calculation logic
Validates domain (x > 0 for logs), then applies PHP log10/log/exp/pow and formats the result.
Logarithms are undefined for non-positive inputs. Very large |x| in antilog may overflow.
Log and Antilog Calculator FAQ
Common questions about this calculator and how to use the results.
When should I use ln instead of log₁₀?
Natural log appears in continuous growth, calculus, and many science formulas.
Can x be negative for log?
No. Real logarithms require a positive argument.
Is log the same as log₁₀?
In many science contexts yes; some math texts use log for ln. This tool labels the base explicitly.
What is e?
e ≈ 2.71828 is Euler’s number, the base of the natural logarithm.
Why did antilog fail?
Extremely large exponents can overflow floating-point range.