Calculate how much extra fuel towing a trailer costs compared to driving without one. See MPG drop and added fuel cost per trip.
Towing a trailer has a significant impact on fuel economy. Most vehicles experience a 25–50% drop in MPG when towing, depending on trailer size, weight, aerodynamics, and driving conditions. This fuel penalty is the largest ongoing cost of towing.
This calculator quantifies the fuel penalty of towing by comparing your normal MPG to your towing MPG. It shows how much extra fuel each trip costs and the annual impact if you tow regularly. Understanding this cost helps you budget for towing trips and make informed decisions about trailer choices.
For example, if your truck gets 20 MPG normally but drops to 12 MPG while towing, you're burning 67% more fuel. On a 500-mile trip at $3.60/gallon, that's an extra $60 in fuel just for towing.
Whether you drive a compact sedan, a full-size SUV, or a pickup truck, accurate towing fuel penalty figures help you plan smarter and avoid costly surprises at the pump or dealership. Use this tool regularly to track changes over time and adjust your transportation budget accordingly.
The fuel penalty of towing is often underestimated or ignored in trip planning. This calculator gives you a concrete dollar figure for added fuel costs, helping you budget accurately and potentially choose lighter, more aerodynamic trailer options. Results update instantly as you adjust inputs, making it easy to explore different scenarios and find the best option for your driving needs and budget.
Normal Gallons = Distance ÷ Normal MPG | Towing Gallons = Distance ÷ Towing MPG | Extra Gallons = Towing Gallons − Normal Gallons | Extra Cost = Extra Gallons × Fuel Price
Result: $60 extra fuel cost for towing
Normal: 500 ÷ 20 = 25 gal ($90). Towing: 500 ÷ 12 = 41.7 gal ($150). Extra fuel: 16.7 gal × $3.60 = $60. MPG penalty: 40% reduction in fuel economy.
Fuel penalty is the largest variable cost of towing. For frequent towers, the annual fuel penalty can reach $1,000–$3,000 or more. Understanding this cost helps you make informed decisions about trailer purchases and trip planning.
Reducing towing speed from 70 to 60 mph reduces aerodynamic drag by about 26% (drag scales with speed squared). This can improve towing MPG by 10–15%, saving $20–50 per long trip.
For most highway towing, the aerodynamic penalty exceeds the weight penalty. A 5,000-lb enclosed trailer often gets better fuel economy than a 3,000-lb open trailer that catches more wind. Flat-front trailers are the worst offenders.
If you tow 5,000 miles annually with a 35% MPG penalty, the extra fuel cost is $600–$1,200 per year. This recurring cost should factor into both trip budgets and the decision of which trailer to buy or rent.
Typical MPG reductions: small utility trailer (10–20%), boat trailer (20–30%), travel trailer (30–45%), large fifth-wheel (35–50%). The actual penalty depends on trailer weight, aerodynamics, terrain, speed, and headwinds.
Two main factors: added weight requires more engine power (especially on hills) and aerodynamic drag from the trailer increases wind resistance. Drag is proportional to the square of speed, so higher speeds dramatically increase the fuel penalty.
Drive slower (55–62 mph), maintain proper tire pressure, keep the trailer loaded low and balanced, use aero-optimized tow mirrors, avoid driving in strong headwinds, and use the most fuel-efficient tow mode. A tonneau cover on pickups can reduce drag slightly.
Diesel engines are more fuel-efficient under load, making them better for towing. A diesel truck might lose 25–30% MPG towing vs. 35–45% for a comparable gas truck. Diesel's higher torque at low RPM also means less downshifting on hills.
Fill the tank, tow a typical load over a measured distance (at least 100 miles), then refill. Divide distance by gallons used. Repeat 2–3 times and average the results. Trip computers in tow vehicles often overestimate MPG.
Size (aerodynamic drag) typically matters more than weight for highway towing. A large, boxy trailer creates enormous wind resistance. An enclosed, aerodynamic trailer of the same weight will have a noticeably lower fuel penalty, especially at highway speeds.