Fuel Cost Calculator

Fuel cost calculations help budget trips and compare vehicle types. For gas/diesel vehicles, the distance is divided by fuel efficiency to compute gallons needed, then multiplied by fuel price. For EVs, distance is divided by efficiency (mi/kWh) and multiplied by the electricity rate. Plug-in hybrids combine both: the electric range covers the first portion, and the gas engine handles the remainder. CO₂ emissions are estimated at 19.6 lbs/gallon for gasoline and 22.4 lbs/gallon for diesel, based on EPA standards.

Practical example: a 500-mile road trip in a gas car getting 30 MPG with gas at $3.50/gallon. Fuel needed = 500 / 30 = 16.67 gallons. Fuel cost = 16.67 × $3.50 = $58.33. CO₂ emissions = 16.67 × 19.6 = 326.7 lbs. Compare with an EV getting 3.5 mi/kWh with electricity at $0.14/kWh: energy needed = 500 / 3.5 = 142.9 kWh, cost = 142.9 × $0.14 = $20.00, CO₂ = 0 lbs (tailpipe, though grid emissions vary).

Compare with a PHEV with 40 miles electric range: first 40 miles on electric = 40 / 3.5 = 11.4 kWh costing $1.60, remaining 460 miles on gas = 460 / 30 = 15.33 gallons costing $53.67, total cost = $55.27. Edge cases: for trips in extreme cold (below freezing), EV range can drop by 30-40% because battery chemistry slows down and cabin heating consumes significant power. In these conditions, adjust EV efficiency downward by 30% for accurate cost estimates.

For diesel vehicles, DEF (diesel exhaust fluid) adds a small additional cost — about $0.02-0.03 per mile. For gasoline direct injection (GDI) engines, actual fuel economy on short trips can be 20-30% worse than the EPA rating because the engine takes longer to reach operating temperature. For towing, fuel economy can drop by 40-60% depending on trailer weight and aerodynamics.