Logarithm Calculator
Log of any positive number in any base.
Amortization schedule
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Showing first 12 of months.
Growth over time
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Introduction
Logarithm Calculator — Log of any positive number in any base. Enter Number, Base to get an instant, accurate result.
Formula
logᵦ(n) = ln(n) / ln(b), using the change-of-base formula.
Step-by-step
- Enter the Number.
- Enter the Base.
- Click Calculate to see your result instantly.
Real-world example
Example: With Number = 100, Base = 10, the Logarithm Calculator gives Result: 2.
Frequently Asked Questions
Can I compute a natural log?
Yes — set the base to e (≈2.71828) or use the scientific calculator's ln() function.
What if n is zero or negative?
Logarithms are only defined for positive n, so the result will be invalid for zero or negative input.
What inputs does the Logarithm Calculator need?
You'll need to provide: Number, Base. All fields use sensible defaults, so you can see a working example immediately and then adjust the values to match your own numbers.
How accurate is the Logarithm Calculator?
The Logarithm Calculator applies the formula exactly as calculated — logᵦ(n) = ln(n) / ln(b), using the change-of-base formula. — so results are precise for the inputs you provide. Accuracy depends on entering correct, realistic input values.
Is the Logarithm Calculator free to use?
Yes, the Logarithm Calculator is completely free, requires no signup, and runs instantly in your browser.
About the Logarithm Calculator
The Logarithm Calculator uses a real, verifiable formula — logᵦ(n) = ln(n) / ln(b), using the change-of-base formula. — so results are accurate every time, not an approximation.