Antilog Calculator
Inverse logarithm — Base 10, Base e (natural), Base 2 & Custom — with step-by-step solution
Select Base
Quick Examples
Step-by-Step Solution
Verification
Antilog Using Characteristic & Mantissa
Used in traditional log table method (base 10 only). Enter the full log value and we do the lookup for you.
Antilog Reference Table (Base 10)
What is an Antilogarithm (Antilog)?
An antilogarithm (or antilog) is the inverse operation of a logarithm. While a logarithm answers "to what power must the base be raised to get this number?", an antilogarithm answers the reverse: "what number do I get when I raise the base to this power?"
Formally, if logb(x) = y, then the antilog is x = by. This relationship is the foundation of every antilog calculation.
where b > 0, b ≠ 1, and y is any real number
Types of Antilogarithms
| Type | Base | Formula | Common Use |
|---|---|---|---|
| Common Antilog | 10 | antilog(y) = 10y | Science, engineering, pH, Richter scale |
| Natural Antilog | e ≈ 2.71828 | exp(y) = ey | Calculus, finance, biology, physics |
| Binary Antilog | 2 | antilog₂(y) = 2y | Computer science, information theory |
| Custom Base | Any b > 0, b ≠ 1 | antilogb(y) = by | Specialized scientific computation |
How to Use This Antilog Calculator
- Select your base: Base 10 (common), Base e (natural), Base 2, or enter a custom base.
- Enter the log value (exponent y) — it can be positive, negative, or a decimal.
- Click Calculate Antilog to see the result instantly.
- Use quick-example buttons to explore common values in one click.
- Expand Step-by-Step Solution to see the full working.
Worked Examples
antilog₁₀(3) = 10³ = 1,000
Verification: log₁₀(1000) = 3 ✓
e² = 2.71828² ≈ 7.3891
Verification: ln(7.3891) ≈ 2 ✓
10⁻² = 1/100 = 0.01
Used in pH: if pH = 2, [H⁺] = 10⁻² = 0.01 mol/L ✓
10^0.5 = √10 ≈ 3.1623
Verification: log₁₀(3.1623) ≈ 0.5 ✓
Antilog with Characteristic & Mantissa (Log Table Method)
In traditional mathematics (and many school exams), antilog is computed using a printed antilog table. A log value like 2.5463 is split into two parts:
- Characteristic = 2 (the integer part). Determines the power of 10.
- Mantissa = 0.5463 (the positive decimal part). Looked up in the antilog table.
Using an antilog table for mantissa 0.5463: look up row 0.54, column 6, mean difference 3 → gives 3519. The antilog = 3519 × 10^(2+1−4) = 351.9. Use our Advanced tab above to replicate this instantly.
Real-World Applications of Antilog
- Chemistry (pH): The concentration of hydrogen ions is [H⁺] = 10^(−pH). At pH 7, [H⁺] = 10⁻⁷ = 0.0000001 mol/L.
- Seismology (Richter Scale): Earthquake energy increases as 10^(1.5 × magnitude). A magnitude-8 quake releases antilog10(12) = 10¹² ergs relative units.
- Finance (Compound Growth): Continuous compounding formula A = P × e^(rt) uses the natural antilog.
- Sound (Decibels): Converting dB back to amplitude ratio: ratio = 10^(dB/20).
- Computer Science: Binary antilog 2^n gives the number of unique values in n bits (e.g., 2^8 = 256 colours in 8-bit colour).
- Biology (Population Growth): Population after time t: N = N₀ × e^(kt), where e^(kt) is the natural antilog.
Key Properties of Antilog
| Property | Formula | Example |
|---|---|---|
| Inverse of log | antilog_b(log_b(x)) = x | antilog₁₀(log₁₀(100)) = 100 |
| Product rule | b^(a+c) = b^a × b^c | 10^(1+2) = 10 × 100 = 1000 |
| Zero exponent | b^0 = 1 | antilog₁₀(0) = 1 |
| Negative exponent | b^(-y) = 1/b^y | antilog₁₀(-3) = 0.001 |
| Fractional exponent | b^(1/n) = n-th root of b | antilog₁₀(0.5) = √10 ≈ 3.162 |
Frequently Asked Questions
What is an antilogarithm (antilog)?
What is the antilog of 2?
How do I calculate antilog manually?
Method 2 — Log table: Split y into characteristic (integer part) + mantissa (decimal part). Locate the mantissa in a printed antilog table to get a 4-digit number, then position the decimal using the characteristic.
What is the difference between base-10 antilog and natural antilog?
Natural antilog (exp) = ey, where e ≈ 2.71828 — used in calculus, finance (continuous compounding), and biological growth models. On a calculator, look for the "e^x" or "exp" key to compute it.