📄 A4 Paper 📏

What an odd number - A4 paper measured at 297mm x 210mm?

The area of:

• A0 = 1,000,000 mm² or 1 m² (not 1 x 1)

• A1 = 500,000 mm²

• A2 = 250,000 mm²

• A3 = 125,000 mm²

• A4 = 62,500 mm²

• A5 = 31,250 mm²

Also for every size, the length to width ratio stays the same.

Imagine A4:

• Length = L

• Width = W

• Its length to width ratio = L / W

Going down to A5:

• Length = W

• Width = L / 2

• Its length to width ratio = 2 W / L

Plugging both ratios together:

L / W = 2 W / L
L² / W² = 2
L / W = √2 ≈ 1.414

With this ratio, an A4 paper with length L and width W where:

• L = √2 W

• L * W = 62,500 mm²

Solving it would get L ≈ 297.302 mm and W ≈ 210.224 mm. No wonder A4 paper measured at 297 mm x 210 mm. 😉