Antilog Calculator
Calculate the inverse logarithm of a number: enter the base b (10 is the default value, enter e for e constant) and the logarithm value y, and the antilog x = bʸ comes back rounded to 10 decimal places — all computed in this browser tab.
Enter the base b and the logarithm value y, then press =. Results appear here.
How it works: the anti-logarithm (inverse logarithm) raises the base b to the power y: if y = logb(x) then x = by. For example, log10(100) = 2, so the antilog of 2 with base 10 is 10² = 100; with base e, antilog(1) = e ≈ 2.7182818285. The base must be greater than 0 and different from 1, and the result is rounded to 10 decimal places. All math happens in this browser tab — nothing is uploaded, stored, or shared.
Enter the base b
10 is the default — the common logarithm you use every day. Type e for the natural base (Euler's number, ≈ 2.71828), or any other positive base such as 2. The base must be greater than 0 and different from 1.
Enter the logarithm value y
This is the exponent side of y = log_b(x): any finite number works, including negatives and decimals, e.g. 2, -3 or 0.30103. Negative y simply gives a result between 0 and 1.
Press = and read x
The result is x = bʸ, rounded to 10 decimal places. For example antilog of 2 with base 10 is 10² = 100, because log₁₀(100) = 2 — the antilog undoes the logarithm.
Common antilog values
| base b | logarithm value y | antilog x = bʸ |
|---|---|---|
| 10 | -3 | 0.001 |
| 10 | -1 | 0.1 |
| 10 | 0 | 1 |
| 10 | 1 | 10 |
| 10 | 2 | 100 |
| 10 | 3 | 1000 |
| 10 | 0.30103 | 2.00000002 |
| 2 | 10 | 1024 |
| e | 1 | 2.7182818285 |
| e | 2 | 7.3890560989 |
Antilog definition
When y = log b(x), the anti-logarithm (or inverse logarithm) is calculated by raising the base b to the logarithm y: x = log b⁻¹(y) = bʸ. For example, log₁₀(5) ≈ 0.69897, so the antilog of 0.69897 with base 10 is 10⁰·⁶⁹⁸⁹⁷ ≈ 5. With base e the antilog is the exponential function: antilog(1) = e ≈ 2.7182818285.
How this calculator works
- Why must the base be greater than 0 and different from 1?
- A logarithm answers "b to what power gives x". With b = 1 every power is 1, so most x have no answer at all; with b ≤ 0 most exponents give no real result (e.g. (-2)^0.5 is not a real number). The calculator rejects those bases with a clear message instead of a made-up number.
- What does entering e do?
- It uses Euler's number e ≈ 2.7182818285 as the base, so the antilog becomes the exponential function eʸ — the inverse of the natural logarithm ln(x).
- How precise are the results?
- Results are rounded to 10 decimal places, matching the reference behavior. Type y = 0.30103 with base 10 and you get 2.00000002, not a fudged 2 — the math tracks your exact input.
- Can y be negative?
- Yes. A negative logarithm value just means a fraction: antilog of -3 with base 10 is 10⁻³ = 0.001, which is exactly what log₁₀(0.001) = -3 says.
Privacy: this calculator runs entirely in your browser tab. Your input and results are never uploaded, stored, or shared.