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Square root of 19

√19 ≈ 4.3589. The square root of 19 is about 4.3589. 19 is not a perfect square, so √19 is irrational: its decimals never end or repeat.

√19 at a glance.
Value4.35889894
Rounded4.4 (1 dp) · 4.36 (2 dp) · 4.359 (3 dp)
Simplest radical form√19
Perfect square?No — between 4² = 16 and 5² = 25
19 squared361

Estimating √19 in your head

Start from the nearest perfect square, 4² = 16. 19 is 3 more than that. Divide the difference by twice the root, 8, and add it:

√19 ≈ 4 + 3 ÷ 8 ≈ 4.375

The true value is 4.3589, so the one-step estimate is off by about 0.016. The estimate always comes out slightly high, and it is closest when 19 is near a perfect square. The method is explained in estimating square roots in your head.

Can √19 be simplified?

No. 19 has no perfect-square factor besides 1, so √19 is already in simplest radical form.

Frequently asked questions

What is the square root of 19?

The square root of 19 is about 4.3589. 19 is not a perfect square, so √19 is irrational: its decimals never end or repeat.

Is 19 a perfect square?

No. It lies between 4² = 16 and 5² = 25.

What is √19 in simplest radical form?

√19 is already in simplest form: 19 has no square factor other than 1.

Practise estimating square roots

Nearby: √18 · √20 · all square roots to 150