Free online square root calculator

How to use

1. Enter the value whose root you want.
2. Set the root degree — 2 for square root, 3 for cube root, etc.
3. The result and expression appear instantly.

The formula

nth root of x = x^(1/n)

For x < 0 and odd n:
  result = −(|x|^(1/n))

For x < 0 and even n:
  result is complex (not real) — error shown

Source: Stewart J. Calculus: Early Transcendentals. 8th ed. §1.5

Worked examples

√9 = 3 — 3² = 9 (perfect square)

√2 ≈ 1.41421356 — irrational, shown to 9 significant figures

∛27 = 3 — 3³ = 27 (perfect cube)

∛(−27) = −3 — (−3)³ = −27 (negative, odd root)

⁴√16 = 2 — 2⁴ = 16 (perfect fourth root)

Common perfect squares and cubes

Notes

• The root degree must be a positive whole number.
• Results are shown to 9 significant figures for irrational roots.
• The square and cube values shown are the original value squared and cubed, not the result.