The first known theoretical calculation of π is credited to Archimedes of Syracuse in ancient Greece, around 250 BCE.

Quick Scoop: Who did the first calculation of pi?

Archimedes did not just measure circles roughly; he used a rigorous geometric method with polygons to pin π between two precise fractions.

He showed that 22371<π<227\frac{223}{71}<\pi <\frac{22}{7}71223​<π<722​, which corresponds to about 3.1418 as a central estimate—astonishingly close to the modern value.

Because of this, many historians describe his work as the first true mathematical calculation (or derivation) of π, rather than a loose measurement.

Before Archimedes: rough discoveries

Long before Archimedes, several civilizations were already using approximate values of the circle ratio we now call π.

  • Ancient Babylonians used values around 3.125 based on practical measurements.
  • Ancient Egyptians (e.g., in the Rhind Papyrus) used a rule equivalent to π ≈ 3.16.

These were more like engineering approximations than a formally justified calculation, which is why Archimedes stands out as the first to calculate π in a rigorous, mathematical way.

Archimedes’ clever idea (mini story)

Imagine Archimedes in Syracuse drawing a circle in the sand, then surrounding it with many-sided polygons, like a 96-sided stop sign wrapped around the circle.

By comparing the perimeters of a polygon inside the circle and a polygon outside it, he trapped the true circumference—and therefore π—between two bounds.

The more sides he used, the tighter the trap on π became, leading to his famous inequalities that are still taught as a classic insight into geometry.

Later improvements around the world

After Archimedes, others pushed π much further, but they were building on the kind of idea he pioneered.

  • Ptolemy (2nd century CE) refined π to about 3.14166 using chord tables.
  • Chinese mathematicians like Liu Hui and Zu Chongzhi later computed π with remarkable accuracy (Zu’s 355/113 was the world’s best for centuries).
  • From the 1600s onward, European mathematicians used infinite series and other advanced tools to reach dozens and then hundreds of digits.

Tiny FAQ-style wrap-up

  • Who did the first calculation of pi?
    Archimedes of Syracuse, using a geometric polygon method around 250 BCE.
  • Did others know about pi before him?
    Yes, Babylonians, Egyptians, and others used approximate values, but without Archimedes’ level of mathematical proof.
  • Why is Archimedes still mentioned every Pi Day?
    Because his work is seen as the first rigorous calculation of π and a milestone in mathematical thinking that still inspires modern celebrations and articles about pi.

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