How to use this natural logarithm calculator
- Enter a positive number x — plain decimals (2, 0.5), scientific notation (5e3, 4e-8, 1.45e12), or the single letter e for Euler’s number (2.718281828…).
- Press Calculate (or hit Enter). The tool shows ln(x) at full double precision — the base-e logarithm of your number.
- Press Copy to put the result on your clipboard, or Reset to start over.
The natural logarithm ln(x) is the logarithm to base e ≈ 2.718281828 — the exponent y such that e y = x. So ln(1) = 0, ln(e) = 1, and ln(5e3) = ln(5000) ≈ 8.517193. It is defined only for x > 0: this calculator reports ln(0) and ln of a negative number as an error, since they are undefined in the real numbers. Everything runs locally in your browser — nothing is uploaded.
Worked examples: ln(2) ≈ 0.69314718, ln(10) ≈ 2.30258509, ln(4e-8) ≈ −17.03438638. More math tools are in Math & Statistics.