Here's the district cost formula: FLOOR(BaseCost * (1 + 9 * FLOOR(100 * MAX(CompletedTechs / 67, CompletedCivics / 50))/100)) Source: https://www.reddit.com/r/civ/comments/5947kp/civ_vi_mechanics_how_district_production_cost/ It's confusing to me so I made a spread sheet to see what actually happens per tech . It's actually pretty simple. Every science tech increases districts by 8.05 hammers. (or 13% per tech) Each culture tech increases districts by 10.8 hammers. (or 18% per tech) You pay the greater of the two. Game speed then alters it accordingly (online speed is half cost, etc). So lets say you are rushing towards Apprenticeship. You must research 6 techs to get there. 6x8.05+60 (base cost) = 108 hammers @ standard speed.