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√2 N decimals Generator

Square root of 2 = 1.41421... up to 1000 decimals. Useful for geometry, ISO A0-A4 paper sizes and irrational study.

The square root of 2 to a thousand decimal places

The square root of 2, roughly 1.414214, is the diagonal of a unit square — and it was the first number proved not to be a fraction. The proof, credited to the Pythagorean school, is a short contradiction argument, and the result was so disturbing to a philosophy holding that everything is expressible as ratios of integers that it produced the legend of Hippasus being thrown into the sea for revealing it.

Choose the places and receive up to a thousand digits, computed by integer square root in arbitrary precision using Newton's method, and checked against published values. The algorithm is the same one taught for extracting roots by hand, only operating on giant integers rather than decimals.

The constant has a quiet everyday presence. A4 paper and the whole A series carry the ratio square root of 2 between long and short side — that is what allows folding the sheet in half and getting the same format, a property no other proportion has. It is also the ratio between semitones in equal temperament raised to the sixth power, which makes the tritone exactly half an octave.

Frequently asked questions

How is it proved irrational?
By contradiction: suppose it is the fraction a over b in lowest terms. Squaring, a squared is 2 times b squared, so a is even. Writing a as 2k and substituting shows b is even too — contradicting the fraction being in lowest terms. Since the assumption leads to contradiction, it is false.
Why does A4 paper use that proportion?
Because it is the only one where halving preserves the format. If the long side is to the short as the square root of 2 is to 1, folding makes the ratio 1 to root 2 over 2 — which is the same proportion. That is why a folded A3 gives exactly A4, with nothing left over.
How does it differ from Pythagoras's constant?
It does not: that is another name for the same number, given precisely because of the link to the theorem. The diagonal of a unit square is the hypotenuse of a triangle with legs of 1, and the root of 1 plus 1 is the root of 2.

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