Logarithm Calculator

Logarithm Calculator is a clean, fast tool for working with logarithms — completely offline. Enter any base and value to get the answer the moment you type, see the change-of-base working, and check the same number in the three standard bases at a glance.

WHAT YOU CAN DO
• Compute log base b of x for any positive base b ≠ 1 and value x > 0
• Quick-pick the common bases e, 10 and 2 with one tap
• Read ln(x), log10(x) and log2(x) side by side
• See the change-of-base formula filled in with your numbers
• Solve the equation log_b(x) = y for whichever of b, x or y is missing

NATURAL, COMMON AND BINARY
The natural log (base e), the common log (base 10) and the binary log (base 2) are all built in, computed from one reliable engine using the change-of-base identity log_b(x) = ln(x) / ln(b).

CLEAR, NOT CLEVER
Logarithms are only defined for positive values. Out-of-domain input — a value of zero or a negative number, or an invalid base — is flagged with a friendly message instead of a wrong answer or a crash.

LEARN AS YOU GO
A built-in Learn tab explains, in plain language, what a logarithm is, the difference between common, natural and binary logs, how change of base works, and where logarithmic scales show up — earthquakes, sound, pH, compound interest and algorithm running time.

PRIVACY
The app collects no personal data and works fully offline — your calculations never leave your device. Ads are served by Google AdMob, which may use an advertising identifier as described in Google's policies.

EDUCATIONAL USE
This app is provided for general and educational use. Results are computed with standard double-precision arithmetic; always double-check critical calculations independently before relying on them.

Light and dark themes, a tiny download, and no clutter. Download Logarithm Calculator and work with logs with confidence.