Four inputs. One number you can defend. Built on the 12% mileage reduction reported across published route-optimization studies — adjust if you have your own data.
The math, in one line
Annual savings = (fleet × daily miles × working days × optimization %) split three ways: fuel saved = miles saved ÷ mpg × fuel price · driver time recovered = miles saved × hrs/mile × wage · maintenance = miles saved × $0.18/mi (US fleet average, AAA 2024). The 12% reduction baseline is a midpoint from published case studies — set it to 0 if you want to see the math fail closed.