Square Calculator (A = a²)

One side length drives everything. Worked example: a = 7 cm → area 49 cm², perimeter 28 cm, diagonal d = 7√2 = 9.90 cm. The diagonal is always √2 ≈ 1.4142 times the side — the basis of the 45° miter cut.

1. 1

   Enter the side a

   Any length unit, kept consistent.

2. 2

   Calculate

   Area, perimeter and diagonal instantly.

3. 3

   Scale check

   Double a → area ×4, perimeter ×2.

• 1

  d = a√2 comes from Pythagoras on two sides

• 2

  a = d/√2 reverses from a measured diagonal

• 3

  1 m² = 10.764 ft² for conversions

• Computing 4a for area (that is perimeter)

• Using 2a instead of a√2 for the diagonal

• Unit slips cm² vs m² (factor 10,000)

• Squaring the diagonal instead of the side