Log Base 2 of 9

Logarithm Calculator
Log base
x

What is log₂ 9?

Answer

log2 9 ≈
3.1699

log2 is the log base 2.

≈ — the logarithm is irrational; the value is rounded to 4 decimal places.

log2 9 is the power you raise 2 to, to get 9: 2y = 9.

2³ = 8 < 9 < 16 = 2⁴, so 3 < log2 9 < 4

log2 9 = ln 9 / ln 2 ≈ 2.197225 / 0.693147 ≈ 3.1699

Oxy

Answer point ≈ (9, 3.1699).

The curve y = log2 x passes through (1, 0) and (2, 1) and rises: for x > 1 the log is positive, for 0 < x < 1 negative.

Log of 9 in different bases
BaseNotationValue
eln 9≈ 2.1972
10log 9≈ 0.9542
2log₂ 9≈ 3.1699

See Also

Log base 2 of nearby numbers

FAQ

What is log₂ 9?

log₂ 9 ≈ 3.1699

How to calculate log₂ 9 on a calculator?

Divide the natural logs: log₂ 9 = ln 9 / ln 2 ≈ 2.197225 / 0.693147 ≈ 3.1699.

What does log without a base mean?

At school and on a calculator, log x without a base is the common log, base 10: log 100 = 2. In Python, math.log(x) is the natural log ln x; in Excel, LN is the natural log and LOG is base 10.