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Square root of 63

√63 ≈ 7.9373. The square root of 63 is about 7.9373, which simplifies to 3√7. 63 is not a perfect square, so √63 is irrational: its decimals never end or repeat.

√63 at a glance.
Value7.93725393
Rounded7.9 (1 dp) · 7.94 (2 dp) · 7.937 (3 dp)
Simplest radical form3√7
Perfect square?No — between 7² = 49 and 8² = 64
63 squared3,969

Estimating √63 in your head

Start from the nearest perfect square, 8² = 64. 63 is 1 less than that. Divide the difference by twice the root, 16, and subtract it:

√63 ≈ 8 − 1 ÷ 16 ≈ 7.938

The true value is 7.9373, so the one-step estimate is off by less than 0.001. The estimate always comes out slightly high, and it is closest when 63 is near a perfect square. The method is explained in estimating square roots in your head.

Simplifying √63

Find the largest perfect square that divides 63: it is 9, since 63 = 9 × 7. Take its root outside: √63 = √9 × √7 = 3√7.

Frequently asked questions

What is the square root of 63?

The square root of 63 is about 7.9373, which simplifies to 3√7. 63 is not a perfect square, so √63 is irrational: its decimals never end or repeat.

Is 63 a perfect square?

No. It lies between 7² = 49 and 8² = 64.

What is √63 in simplest radical form?

√63 = √(9 × 7) = 3√7.

Practise estimating square roots

Nearby: √62 · √64 · all square roots to 150