Square Root of 676

The square root of 676 is exactly 26, because 26 × 26 = 676. The negative number −26 squares to 676 too.

Whole numbers, decimals or fractions like 9/16. Negative numbers have no real root.
Decimal
26
Both real square roots
±26x² = 676 has two real solutions
Perfect power?
Yes
√67626

Show the work

  1. 676 is a perfect square: 262 = 676.
  2. So √676 = 26.

√676 at a glance

Exact value
26
Decimal (10 places)
26
Rounded
26
Perfect square?
Yes — 26²
Rational?
Rational (whole number)
Both square roots
±26
Prime factorization
2² × 13²
Cube root
8.776383

How to simplify √676

Write 676 as a product of primes and halve every exponent. Because each exponent is even, nothing is left under the radical sign:

676 = 2² × 13²
√676 = 2 × 13 = 26

676 has 5 factor pairs (1 × 676, 2 × 338, 4 × 169, 13 × 52, 26 × 26). The pair with two equal numbers, 26 × 26, is what makes it a perfect square — and why it has an odd number of factors.

Every perfect square is also a sum of consecutive odd numbers starting at 1. Here 676 = 1 + 3 + 5 + 7 + … + 51, the first 26 odd numbers.

Where √676 sits between perfect squares

676 is 26². The perfect squares on either side are 625 (25²) and 729 (27²), so the gaps are 51 below and 53 above — consecutive squares always differ by consecutive odd numbers.

2525² = 6252626² = 6762727² = 729√676 = 26
√676 on a number line, with tenths marked between 25 and 27.

Finding √676 with the Babylonian method

Picture a rectangle with an area of 676 and one side x; the other side must be 676 ÷ x. Averaging the two sides gives a rectangle that is closer to a square, and the side of that square is exactly √676.

xnext = (x + 676 ÷ x) ÷ 2

To show the method at work on a perfect square, start one above the answer, at 27:

StepGuess x676 ÷ xAverageCorrect decimals
127.000000000025.037037037026.01851851851
226.018518518525.981494661926.00000659025
326.000006590225.999993409826.0000000000all 10 shown

The count of correct decimals went 1, 5 and all 10 over 3 steps — roughly doubling each time — until the guess matched √676 = 26.0000000000 to every decimal shown.

√676 in geometry and everyday measurements

  • 676 square feet is 62.8 m². Laid out as a square — a small house footprint or a lot — it is exactly 26 ft (26 ft) on a side.
  • 676 = 10² + 24², so 10, 24 and 26 form a Pythagorean triple: a right triangle with legs 10 and 24 has a hypotenuse of exactly 26.
RootSimplest formDecimalPerfect square?
√673√67325.9422No
√674√67425.9615No
√67515√325.9808No
√6762626.0000Yes
√677√67726.0192No
√678√67826.0384No
√679√67926.0576No
  • The cube root of 676 is about 8.776383.
  • Taking the square root twice gives the fourth root: √26 ≈ 5.099020.
  • Because 676 = 4 × 169, the root is twice √169: 2 × 13 ≈ 26.

Frequently asked questions

What is the square root of 676?

The square root of 676 is 26, because 26 × 26 = 676. Strictly, 676 has two square roots, 26 and −26; the √ symbol means the positive one.

Is the square root of 676 rational or irrational?

Rational. 676 is a perfect square, so its square root is the whole number 26.

Can √676 be simplified?

Yes, all the way to a whole number: √676 = 26.

What is √676 rounded to two decimal places?

√676 is exactly 26, or 26.00 written to two decimal places.

Need a different value? Use the Square root calculator, or browse the Square roots 1–1,000.