What is the cube root of 18?

The cube root of 18 is cbrt18. In decimal: cbrt(18) approximately 2.6207413942 This is irrational. cbrt(18) approx 2.62074 is irrational. 18 = 2 x 3^2, no perfect cube factor.

Is 18 a perfect cube?

No. 18 is not a perfect cube. 2^3 = 8 and 3^3 = 27. Since 18 falls between these, cbrt(18) is not an integer. Nearest perfect cubes: 8 (= 2^3) and 27 (= 3^3).

What is cbrt(18) cubed?

(cbrt(18))^3 = 18. This follows from the definition: cbrt(n) is the number that when cubed gives n. So (cbrt(18))^3 = 18 always.

How is cube root different from square root?

Square root: sqrt(18) approximately 4.242641. Cube root: cbrt(18) approximately 2.620741. Key differences: - Cube roots exist for negative numbers: cbrt(-8) = -2. Square roots of negatives are imaginary. - Cube roots grow more slowly than square roots. - Perfect cubes are rarer than perfect squares.

What are the perfect cubes from 1 to 30?

Only three: 1 (= 1^3), 8 (= 2^3), and 27 (= 3^3). 18 is not a perfect cube. The next perfect cube after 27 is 64 (= 4^3).

Cube Root of 18 — cbrt(18) = cbrt18

The cube root of 18 is cbrt18. In decimal, cbrt(18) is approximately 2.620741 (irrational — the decimal never ends or repeats). This page shows the exact value, simplified radical form, decimal to 20 decimal places, step-by-step working, and a 3D cube visualisation....

∛18 = ?

CUBE ROOT OF 18

∛18

≈ 2.6207413942

Irrational — decimal never ends or repeats

Exact form

∛18

Decimal (6dp)

2.620741

Decimal (10dp)

2.6207413942

Is perfect cube?

(∛18)³

18 ✓

Between

2 and 3

DECIMAL PRECISION

∛18 ≈ 2.6207413942

STEP-BY-STEP

Prime factorisation: 18 = 2 × 3 × 3

No perfect cube factor — ∛18 is already in simplest form

2³ = 8 < 18 < 27 = 3³ → ∛18 between 2 and 3

∛18 ≈ 2.6207413942

FUN FACT

cbrt(18) approx 2.62074 is irrational. 18 = 2 x 3^2, no perfect cube factor.

NUMBER LINE (∛18 ≈ 2.6207)

∛18

CUBE WITH VOLUME = 18

NEARBY PERFECT CUBES

∛1= 11³ = 1

∛8= 22³ = 8

∛27= 33³ = 27

∛64= 44³ = 64

∛125= 55³ = 125

CUBE ROOT LAWS

∛18 × ∛18 × ∛18= 18

(∛18)³= 18

∛(18 × 8)= 2∛18 ≈ 5.2415

∛(18 / 8)= ∛18/2 ≈ 1.3104

∛18 × ∛19≈ 6.9932

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HOW TO CALCULATE

1
Find the prime factorisation of 18: 18 = 2 x 3 x 3. Look for any prime appearing 3+ times.
2
No factor appears 3+ times, so cbrt(18) cannot be simplified and stays as cbrt(18).
3
Locate cbrt(18) between integers: 2^3 = 8 < 18 < 27 = 3^3. So cbrt(18) is between 2 and 3.
4
Decimal: cbrt(18) approximately 2.6207413942. Verify: (2.620741)^3 approximately 18.

WORKED EXAMPLE

cbrt(18): not a perfect cube. Factorisation: 18 = 2 x 3 x 3. Simplified: cbrt18. Decimal: cbrt(18) approximately 2.6207413942.

FREQUENTLY ASKED QUESTIONS

OTHER CUBE ROOTS

∛1 ∛2 ∛3 ∛4 ∛5 ∛6 ∛7 ∛8 ∛9 ∛10 ∛11 ∛12 ∛13 ∛14 ∛15 ∛16 ∛17 ∛19 ∛20 ∛21 ∛22 ∛23 ∛24 ∛25 ∛26 ∛27 ∛28 ∛29 ∛30

Bold bordered = perfect cubes (∛1=1, ∛8=2, ∛27=3)

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Last updated: April 28, 2026 · Verified by EagleCalculator team · Eagle-eyed accuracy for every calculation.