Log Calculator
A simple calculator to compute logarithms with customizable base.
Published by:
isCalculator Editorial Team
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How to use this tool?
This calculator computes the logarithm of a number x with a given base b, using the formula: logb(x) = ln(x) / ln(b).
- Enter the Number (x): Type a positive number (e.g., 100, 0.5). Must be greater than 0.
- Enter the Base (b): Type the base (e.g., 10 for common log, 2 for binary log). Must be positive and not equal to 1. Default is 10.
- Click "Calculate Log": The result appears below, rounded to 6 decimal places.
Example: Number = 100, Base = 10 → Result = 2.000000 (since 10² = 100).
Tip: Use any positive number (including decimals) and any valid base. The calculator uses natural logs internally for accuracy.
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Frequently Asked Questions
A logarithm answers the question: 'To what exponent must the base be raised to produce a given number?' For example, log10(100) = 2 because 10^2 = 100.
Any positive base except 1. Common bases include 10 (common log), e (natural log), and 2 (binary log).
No, the calculator only accepts positive numbers. Logarithm of a non-positive number is undefined in real numbers.
