Math Tools

Logarithm & Exponential Calculator

Compute log base 10, natural log, any custom-base log, powers, roots, and exponential values in one place.

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Logarithm & Exponential Calculator
Calculate logs, natural logs, powers, roots and e^x
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Disclaimer. This calculator is provided for educational and general-purpose use. Verify critical or high-stakes calculations independently before relying on them. Read full disclaimer →

About Logarithm and Exponential Calculator

Logarithms and exponentials are inverse operations. Log base b of x equals y means b raised to y equals x. Common logarithm uses base 10; natural logarithm ln(x) uses base e (approximately 2.71828). Key identities: log(a times b) = log(a) + log(b); log(a divided by b) = log(a) minus log(b); log(a to the n) = n times log(a).

The exponential growth model A = A0 times e to the rt is used for population growth, continuously compounded interest, radioactive decay, and epidemic modelling. Decibels in audio use log base 10. pH in chemistry = negative log of hydrogen ion concentration. The Richter earthquake scale uses log base 10. The natural log derivative equals 1 over x, making it fundamental in calculus and solving differential equations.

Frequently Asked Questions

log₁₀ (common logarithm) uses base 10. ln (natural logarithm) uses base e, approximately 2.71828. The custom-base option lets you compute the logarithm in any base you choose, using the change-of-base formula log_b(x) = ln(x)/ln(b).
It uses the change-of-base formula: log_b(x) = ln(x) ÷ ln(b). For example, log₂(8) = ln(8)/ln(2) = 2.079.../0.693... = 3, since 2³ = 8.
Decibels in audio measurement, pH in chemistry (negative log₁₀ of hydrogen ion concentration), and the Richter earthquake magnitude scale are all built on base-10 logarithms. The exponential growth model A = A₀ × e^(rt) similarly underlies population growth, continuously compounded interest, radioactive decay and epidemic modelling.
JavaScript's numbers max out around 1.8×10³⁰⁸. e^x exceeds that limit once x is greater than about 709, and 10^x exceeds it once x is greater than about 308. Rather than showing Infinity or a nonsensical result, the calculator explicitly flags these as Overflow beyond those thresholds.
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