Antilog Calculator
Find the antilogarithm of a number for any base (10, e or custom) in seconds, reversing a logarithm instantly.
The logarithm base, e.g. 10 or e.
Antilogarithm = base raised to the exponent. Base must be positive and not equal to 1.
Antilogarithm
100
10 ^ 2
Check
log of 100
base 10 = 2
If logₐ(x) = y, then the antilogarithm is x = a^y. This undoes a logarithm for any positive base.
Last updated: January 2026
How this calculator is verified
Checked by True Calculator automated test suite on
- Formula verified against a published worked example in the automated test suite
- Edge cases (zero, negative, boundary and unit-mismatch inputs) covered by unit tests
The full verification method is on our how we verify page. Found an error? Tell us and we will re-check it.
When to Use This Calculator
Use the antilog calculator whenever a log-scale reading must be converted back to the original quantity — pH values to hydrogen-ion concentration, decibel readings to sound intensity, Richter magnitudes to energy ratios, or chemistry and physics problems built on log tables. Indian students preparing for JEE and NEET regularly need the reverse of logarithms, since most exam tables give logs and expect candidates to invert them, and this calculator removes the table work. Lab analysts use it to turn instrument readings that come out on log scales back into concentrations, while seismology and audio engineers apply the same inverse to magnitudes and sound levels. Because it accepts any positive base other than one, it covers common logs, natural logs and binary logs in one tool.
How to Use This Calculator
- Step 1: Choose the base — 10 for common logarithms, 2 for binary, e for natural logs.
- Step 2: Enter the logarithm value, such as 2 or 0.3010.
- Step 3: Read the antilog, which is the base raised to that power.
- Step 4: Use the reverse direction to move between log-scale readings and original numbers.
Worked Example
A chemistry student in Pune knows that log₁₀ 2 is about 0.3010 and wants the original number. Entering base 10, value 0.3010 returns 1.9999, effectively 2 — the antilog undoes the logarithm. Base 10 with value 2 gives 100, and base 10 with value −1 gives 0.1, since 10⁻¹ = 0.1. In binary work, the antilog of 3 in base 2 is 8. These inverses move comfortably between log scales and original values for pH, decibels and Richter-scale problems.
Tips and Common Mistakes
- •Tip 1: Use base 10 for common log tables and base e for natural-log calculations such as continuous growth.
- •Tip 2: A negative logarithm value is fine — it produces a result between zero and one, like 10⁻¹ = 0.1.
- •Tip 3: Check that the result makes sense: the antilog of 2 in base 10 must be near 100 by definition.
- ✗Mistake 1: Entering base 1 or a base of zero or below — such bases are invalid, and the calculator returns a hint.
- ✗Mistake 2: Confusing antilog with log — the antilog is the exponentiation, the reverse of taking a logarithm.
Frequently Asked Questions
What is an antilogarithm?
The antilogarithm is the inverse operation of a logarithm: if logₐ(x) = y, then the antilog of y to base a is a^y = x. For base 10, the antilog of 2 is 100 because 10² = 100.
How do I find the antilog of a number in base 10?
Raise 10 to that number. For example, the antilog of 2.301 is 10^2.301 ≈ 200. Enter 10 as the base and 2.301 as the exponent in the calculator to verify.
What are common uses of antilogs in India?
Antilogs are used in chemistry and biology for pH and concentration problems, in audio for decibel calculations, and in finance to convert log returns back into prices. Students preparing for JEE and NEET encounter them regularly.
Can the base of an antilog be any number?
Yes, any positive base other than 1 works. Base 10 and base e (natural antilog) are most common, but base 2 is used in computer science. The calculator accepts any valid base.
What inputs does the calculator reject?
A base of zero, one or a negative number is rejected, because these do not define valid logarithms, and so do results that overflow to infinity. You will see a friendly hint asking for a valid base.
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