Pi Approximation Day 2026 – July 22

Key facts

• Pi Approximation Day is observed every year on July 22.
• The day honors the mathematical constant pi through the fraction 22/7.
• The first calculation of pi was performed by Archimedes of Syracuse around 250 BC.
• The Greek symbol pi (π) was first used by Welsh mathematician William Jones in 1706 and popularized by Leonhard Euler in 1737.
• The first computer calculation of pi was done in 1957 using an ENIAC computer, achieving 2,037 digits.
• As of 2022, the record for calculating digits of pi stands at 100 trillion, achieved by Google Cloud.
• Pi Approximation Day differs from Pi Day (March 14) which uses the decimal representation 3.14.