The Parthenon is one of the most iconic and impressive buildings of the ancient world and it remains a remarkable structure to this day. When one sees the resilient and bold construction, combined with the detail of its intricate decoration, it begs the question “How much did that cost to build?” This study uses a combination of ancient texts and contemporary comparisons to create a quantitative estimate for the amount and cost of the materials used, and manpower required, to gather and transport materials to the site, then build and decorate the Parthenon. The building costs are initially estimated in the currency used at the time, the Athenian Drachm. Although there is no definitive method for comparison between 5th Century Drachm and modern currency, further use of ancient texts provides an approximate modern-day cost for the building of 327 million USD but could cost up to 1 billion USD. This project covers a field of research which is rarely considered compared to other areas in classical history and will help to contribute to this field of study.