Logarithm Calculator
Calculate common, natural and arbitrary-base logarithms.
Logarithm Calculation
Antilog (Exponent) Calculation
Logarithm Rules
- loga(M × N) = logaM + logaN
- loga(M / N) = logaM - logaN
- loga(Mn) = n × logaM
- logaN = ln(N) / ln(a)（Change of base）
- logaa = 1, loga1 = 0
Common Log Values
| N | lg(N) | ln(N) |
|---|---|---|
| 1 | 0 | 0 |
| 2 | 0.3010 | 0.6931 |
| e | 0.4343 | 1 |
| 3 | 0.4771 | 1.0986 |
| 5 | 0.6990 | 1.6094 |
| 10 | 1 | 2.3026 |
| 100 | 2 | 4.6052 |
| 1000 | 3 | 6.9078 |
Usage Instructions
Features
The logarithm calculator supports common log (lg), natural log (ln) and arbitrary-base logarithms, plus antilog (exponent) calculation.
Steps
Enter the number N → Optionally enter base a for arbitrary-base log → Click "Calculate" to view the result; enter a log value below to compute its antilog.
Notes
N must be greater than 0; base a must be greater than 0 and not equal to 1; all calculations run locally in your browser.