How to Simplify Square Roots (Radicals) in 3 Steps

Published 15 November 2026 · Math

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Simplifying a square root means writing it so no perfect square is left under the √ sign. Teachers and exam boards expect answers like 6√2 rather than √72. Our square root calculator does it instantly, but here is how to do it by hand.

Step 1: Know your perfect squares

4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144…

Step 2: Find the largest perfect square factor

For √72, the factors include 4, 9 and 36. The largest perfect square is 36, so 72 = 36 × 2.

Step 3: Split and take the root

√72 = √36 × √2 = 6√2

Worked examples

RootSplitSimplified
√5025 × 25√2
√4816 × 34√3
√200100 × 210√2
√18036 × 56√5
√459 × 53√5

Estimating a square root

Find the perfect squares either side. √40 lies between √36 = 6 and √49 = 7, closer to 6, so about 6.3 (the exact value is 6.3246).

Can you add square roots?

Only like terms: 3√2 + 5√2 = 8√2, but √2 + √3 cannot be combined. Simplify first – √8 + √18 = 2√2 + 3√2 = 5√2.

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