The square root of 18 is 4.24264069 (rounded to 8 decimal places).
The square root of 18 is 4.24264069 (rounded to 8 decimal places).
It is not a perfect square, so the root is irrational. In simplest radical form, √18 = 3√2, because 18 = 9 × 2.
18 lies between the perfect squares 16 (4²) and 25 (5²), so √18 is between 4 and 5. Our answer 4.24264069 fits that range.
You can check it by squaring the result: 4.24264069² ≈ 18.
| √18 | = 4.24264069 |
| 4.24264069² | = 18 |
| ∛18 | = 2.620741 |
| Number | Square root | Note |
|---|---|---|
| 14 | 3.741657 | |
| 15 | 3.872983 | |
| 16 | 4 | perfect square |
| 17 | 4.123106 | |
| 18 | 4.242641 | this page |
| 19 | 4.358899 | |
| 20 | 4.472136 | |
| 21 | 4.582576 |
The square root of 18 is 4.24264069 (rounded to 8 decimal places).
No. The nearest perfect squares are 16 and 25.
Irrational. Its decimal never ends or repeats.
The cube root of 18 is about 2.620741.
Yes. Use the calculator on this page, or open the full free Scientific Calculator with memory, history and keyboard support.