Math & Scientific
Logarithm Calculator
Logarithm — it evaluates the logarithm using log_b(x) = ln(x) ÷ ln(b) for the base you select. This page runs that same calculation on your numbers, in your browser: no signup, no uploads, nothing stored.
Want to work through a calculation? Logarithm Calculator does it from your number and base and shows the result clearly, with everything calculated in your browser.
About this calculator
It evaluates the logarithm using log_b(x) = ln(x) ÷ ln(b) for the base you select. That is the whole of the calculation — the mistakes happen in the inputs. It matters when you need the exact relationship checked quickly rather than worked through by hand. Worked example: log₁₀(1000) = 3 because 10³ = 1000; and ln(e) = 1. Use the calculator with your own figures; it runs entirely on your device.
How to use
- Enter the number (n) and the base (b, or e for natural log).
- Press Calculate to run the logarithm calculator.
- Read the result: log_b(n), plus ln and log₁₀ for reference.
- Press Reset to clear the logarithm calculator and start again.
Why use Logarithm Calculator
Fast
Calculations run in your browser. No round trip to a server.
Private
Your inputs never leave your device. Nothing is uploaded.
Free
No signup, no paywall, no ads-in-results, no watermarks.
Accurate
Based on standard, well-established formulas.
Mobile-ready
Optimised for phones, tablets, and desktops alike.
Transparent
Honest disclaimers wherever browser limits or regional rules apply.
Common uses
Use it when revising for exams
Use it for verifying answers from a textbook
Logarithm in competitive-exam practice
Logarithm in statistics and data coursework
Use it for understanding a formula's behaviour
Use it when preparing worksheets
Technical notes
Logarithm Calculator evaluates the logarithm using log_b(x) = ln(x) ÷ ln(b) for the base you select.
Inputs are taken exactly as entered, so check for typos before trusting an answer.
Nothing you type is uploaded — the calculation happens entirely on your device.
FAQ
What bases can I use?
Any positive base except 1. Enter a number for a custom base, or type e for the natural logarithm.
What does log_b(x) mean?
The power to which the base b must be raised to get x — for example log₁₀(100) = 2.
What do I enter in the Logarithm Calculator?
The number (n) and the base (b); the result also shows ln and log₁₀ for reference.
Does the Logarithm Calculator send my data to a server?
No — the Logarithm Calculator runs entirely in your browser, so the numbers you enter never leave your device.
Worked example
log₁₀(1000) = 3 because 10³ = 1000; and ln(e) = 1.