Square root of 42

√42 ≈ 6.4807

√42 is an irrational number, so its decimals never end or repeat. It sits between 6 and 7 because 6² = 36 and 7² = 49.

√42 rounded

Simplest radical form

42 has no perfect-square factor other than 1, so √42 is already in simplest radical form.

Check the answer

6.4807 × 6.4807 ≈ 41.9995, which is very close to 42.

Need another number? Use the square root calculator (also cube roots and other roots).

Square roots near 42

All square root answers · Exponent calculator