Find Log Calculator
Find log calculator works out Result and Expression from What to calculate, Base and Custom base. The default figures on this page give result of 3; change any entry and the result, the working and the sources update together.
Your figures
Updates as you typeHow this is worked out
3 steps
- Change of base: log_10(1000) = ln(1000) / ln(10).
- ln(1000) = 6.90775527898, ln(10) = 2.30258509299.
- Divide: 6.90775527898 / 2.30258509299 = 3.
Its 5 worked examples are re-run on every release, last on 15 September 2026. What changed
Sources and references
2 sources
What the find log calculator calculates
Computes log base n, natural log and binary log of a value, the antilogarithm b^y, the change-of-base identity, and the product, quotient and power logarithm laws.
How to use this find log calculator
Enter What to calculate, Base, Custom base and Value. Result updates as you type, and “Use a worked example” loads checked figures you can adjust. Change one figure at a time to see what drives the result.
How the result is worked out
Open “How this is worked out” beside the result for the step-by-step calculation behind Result, Expression and Natural log (ln).
The method follows NIST Digital Library of Mathematical Functions, 4.2 Exponential and Logarithmic Functions (change of base 4.2.5, log laws 4.6) and Abramowitz & Stegun, Handbook of Mathematical Functions, Section 4.1 (logarithmic function).
log base 10 of 1000 example
With What to calculate: log, Base: 10, Value: 1000, the calculator returns Result: 3. This example is checked against an independent source in the test suite.
What you can compare
Change one input at a time to see how it affects Result, Expression and Natural log (ln). The inputs you can vary are What to calculate, Base, Custom base, Value, Second value and Logarithm law.
Results are general information, not financial, tax, legal, medical or engineering advice. Check any decision that matters with a qualified professional.
See something wrong? Report a problem with this calculator
Frequently asked questions
How do you find logs on a calculator?
Computes log base n, natural log and binary log of a value, the antilogarithm b^y, the change-of-base identity, and the product, quotient and power logarithm laws. Open “How this is worked out” beside the result to see each step for your own figures.
What is the formula to find log?
On the figures this page opens with — value 1,000 — the result is 3. No single number fits everyone: change any figure above and the answer updates as you type, with each step of the arithmetic beside it.
How to find log calculator trick?
It needs What to calculate, Base, Custom base, Value, Second value and Logarithm law. Nothing else is required, and the figures stay in your browser.
What is the easiest way to calculate logarithms?
The result gives Result, Expression, Natural log (ln), Common log (base 10), Binary log (base 2) and Change-of-base working, each labelled with its unit so the figure can be read on its own.
What information do I need for the find log calculator?
You need What to calculate, Base, Custom base, Value, Second value, Logarithm law and Power p. The page opens with default figures that give result of 3, so you can see the scale before entering your own.
What does this find log calculator show?
It shows Result, Expression, Natural log (ln), Common log (base 10), Binary log (base 2), Change-of-base working, Antilog check (base^result) and Combined logarithm, with the working and any warnings for your entries.