Logarithm Calculator
Calculate logarithms of any base. Compute log_b(x) = ln(x)/ln(b) for common, natural, and custom base logarithms.
Expand logarithmic expressions step by step using product, quotient, and power rules. Supports any base with numeric evaluation, term breakdown bars, and a complete log rules reference table.
| Rule | Formula | Example |
|---|---|---|
| Product Rule | log_b(MN) = log_b(M) + log_b(N) | log(3·5) = log 3 + log 5 |
| Quotient Rule | log_b(M/N) = log_b(M) − log_b(N) | log(8/2) = log 8 − log 2 |
| Power Rule | log_b(M^n) = n · log_b(M) | log(x³) = 3·log(x) |
| Change of Base | log_b(x) = log_a(x) / log_a(b) | log₂(8) = ln 8 / ln 2 |
| Log of 1 | log_b(1) = 0 | log 1 = 0 |
| Log of base | log_b(b) = 1 | log₁₀(10) = 1 |
| Log of power of base | log_b(b^n) = n | log₂(2⁵) = 5 |
| Inverse | b^(log_b(x)) = x | 10^(log 5) = 5 |
| Term | Value | Power | log(term) | Contribution |
|---|---|---|---|---|
| x | 4.0000 | 2 | 0.602060 | 1.204120 |
| y | 9.0000 | 3 | 0.954243 | 2.862728 |
Expanding logarithmic expressions is one of the most common operations in algebra and precalculus. By applying the three fundamental logarithm rules — the product rule, quotient rule, and power rule — you can break down complex log expressions into simpler parts. This is essential for solving equations, simplifying expressions, differentiating and integrating, and understanding the behavior of exponential processes.
This Expanding Logarithms Calculator takes your log expression and expands it step by step, showing exactly which rule is applied at each stage. Enter the base, specify the terms and their powers, and choose whether they are multiplied (product) or divided (quotient). The calculator writes out the full expansion, from the original condensed form to the final expanded result.
Beyond symbolic expansion, the calculator also provides numeric evaluation — substitute values for variables and see the computed result. Term contribution bars visualize how much each term adds to (or subtracts from) the total value, making it easy to understand the relative importance of each factor. Eight presets demonstrate a range of common expressions, and the built-in reference table lists all key logarithm rules with examples. Whether you are a student learning log properties, a teacher building lesson materials, or someone who needs symbolic expansion for applied math, the page keeps the algebraic and numeric views aligned.
Logarithm expansion is one of those topics where rule application matters more than raw calculation speed. This calculator keeps the original expression, the expanded form, and the specific log rules together so you can see exactly how the rewrite happened.
It is especially useful when you want to compare symbolic expansion with a numeric check. The term contribution view makes the expanded expression easier to interpret instead of leaving it as a formal rewrite only.
Product rule: log_b(MN) = log_b(M) + log_b(N). Quotient rule: log_b(M/N) = log_b(M) − log_b(N). Power rule: log_b(M^n) = n · log_b(M).Result: Original Expression shown by the calculator
Using the preset "log₂(8x)", the calculator evaluates the expanding logarithms setup, applies the selected algebra rules, and reports Original Expression with supporting checks so you can verify each transformation.
The calculator takes the condensed logarithmic expression, applies the product, quotient, and power rules in sequence, and then presents the expanded form together with any numeric evaluation you request.
Start with the original expression, then compare it with the expanded form and the rule list. If numeric values are present, the contribution bars help show which expanded terms are adding or subtracting the most.
Work one product example, one quotient example, and one power example. Seeing those three transformations side by side is usually enough to make the log rules much easier to recognize.
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Expanding a logarithm means rewriting a single log of a product, quotient, or power as a sum, difference, or multiple of simpler logarithms using the product, quotient, and power rules.
No. There is no log rule for sums or differences inside a logarithm. log(x + y) cannot be simplified further using standard log properties.
The product rule states that log_b(MN) = log_b(M) + log_b(N). It converts multiplication inside the log into addition outside.
The quotient rule states that log_b(M/N) = log_b(M) − log_b(N). It converts division inside the log into subtraction outside.
Expand when simplifying or differentiating complex expressions. Condense (do the reverse) when solving logarithmic equations or combining terms.
The rules work for any valid base (b > 0, b ≠ 1). The expansion steps are the same for log, ln, log₂, or any other base — only the notation changes.
Calculate logarithms of any base. Compute log_b(x) = ln(x)/ln(b) for common, natural, and custom base logarithms.
Convert between exponential form (b^x = y) and logarithmic form (log_b(y) = x). Solve for any variable — base, exponent, or result — with reference tables and visual comparison bars.
Calculate the natural logarithm ln(x) = logₑ(x). See ln value, e^ln(x) verification, derivative 1/x, integral, and a full reference table of common ln values.