Skip to main content
AI-PoweredDecision ToolsFree — No sign-up

Fuel Cost Calculator

A 300-mile trip at 25 MPG and $3.50/gallon costs exactly $42. Your daily 30-mile commute runs about $4.20 each way. Plug in any distance, your car's MPG, and local gas price to see the total fuel cost, cost per mile, and CO2 footprint. Works in both US and metric units for road trip budgeting or commute cost comparison.

By SplitGenius TeamUpdated February 2026

A 300-mile trip in a 25 MPG car at $3.50/gallon costs $42 and uses 12 gallons of gas. Enter your distance, fuel efficiency, and gas price to see total fuel cost, cost per mile, and CO2 emissions.

Trip Distance

Fuel Efficiency

US average: 25.4 MPG. Hybrids: 45–55 MPG. Trucks: 15–20 MPG.

Fuel Price

$

US national average: ~$3.30–$3.60/gallon (regular unleaded).

How This Calculator Works

1

Enter Your Details

Fill in amounts, people, and preferences. Takes under 30 seconds.

2

Get Fair Results

See an instant breakdown with data-driven calculations and Fairness Scores.

3

Share & Settle

Copy a shareable link to discuss results with everyone involved.

Frequently Asked Questions

People Also Calculate

Gas Split

A 300-mile road trip at 25 MPG and $3.50/gal costs $42 in gas — $10.50 each for 4 passengers. Calculate fuel costs and split with optional driver discount.

Cost Per Mile

The average car costs $0.68/mile — $8,160/year at 12,000 miles. Calculate your true driving cost including fuel, insurance, depreciation, and maintenance.

Car Payment

A $35,000 car at 6.5% APR for 60 months costs $685/month. Factor in your down payment, trade-in, and sales tax to see your real monthly auto loan payment.

Car Afford

On $5,000/month income with a 15% transport budget, you can afford a $35,000 car — but true monthly cost is $990 with insurance, fuel, and maintenance.

Unit Converter

Convert length, weight, volume, temperature, area, speed, time, and data units instantly. See the formula and all common equivalents at once.

Trip Expenses

After a group trip, someone always overpaid and someone always "forgot." Track every expense, see who owes whom, and settle up in the fewest payments possible.

Rent vs Buy

At 7% mortgage rates, buying isn't automatically smarter than renting. Compare true costs over 1-30 years including equity, taxes, maintenance, and opportunity cost.

Net Effective Rent

A $3,000/mo apartment with 2 months free actually costs $2,500/mo. Convert any concession package into the real monthly cost and compare up to 10 apartments.

Renters Insurance

Renters insurance runs $15-30/mo for $30K in coverage. Estimate your premium, compare individual vs. joint roommate policies, and find the smarter option.

Explore 182+ Free Calculators

Split rent, bills, tips, trips, wedding costs, childcare, and more.

Browse All Calculators

Gas Prices in 2026: What You're Actually Paying

The national average gas price fluctuates between $3.00 and $4.00 per gallon, but where you live matters more than national headlines. California drivers regularly pay $4.50–$5.50/gallon while Texas and Gulf Coast states hover near $2.80–$3.20. The difference adds up fast: a 15,000-mile year at 25 MPG costs $1,680 in Texas vs $2,940 in California—$1,260/year just from location.

Gas prices follow seasonal patterns. Summer blend fuel (required April through September in most states) costs 15–40 cents more per gallon than winter blend. If you're planning a road trip, filling up before the summer switch in mid-April saves real money on long drives.

Average Gas Prices by Region (2026)

RegionRegularPremiumAnnual Cost (25 MPG, 12K mi)
Gulf Coast (TX, LA)$2.95$3.55$1,416
Southeast (FL, GA, NC)$3.15$3.75$1,512
Midwest (IL, OH, MI)$3.30$3.95$1,584
Northeast (NY, NJ, MA)$3.50$4.20$1,680
West Coast (CA, WA, OR)$4.60$5.25$2,208

Source: EIA weekly retail gasoline prices, averaged over 2025–2026. Annual cost assumes 12,000 miles at 25 MPG using regular unleaded.

MPG Comparison: How Much Your Vehicle Costs to Drive

Fuel efficiency is the single biggest lever you control. The difference between a 20 MPG truck and a 35 MPG sedan on a 300-mile trip is $22.50 in fuel savings at $3.50/gallon. Over 15,000 annual miles, that gap widens to $1,125/year.

Vehicle TypeAvg MPG300-Mile Trip CostAnnual Fuel (15K mi)Cost/Mile
Full-Size Truck18$58.33$2,917$0.194
Large SUV22$47.73$2,386$0.159
Midsize Sedan30$35.00$1,750$0.117
Compact Car35$30.00$1,500$0.100
Hybrid50$21.00$1,050$0.070

Based on $3.50/gallon. Real-world MPG varies by driving conditions—city driving typically gets 15–25% worse fuel economy than highway cruising.

Road Trip Fuel Cost Examples

Planning a drive? Here's what popular routes actually cost in fuel at $3.50/gallon in a 25 MPG car:

RouteDistanceGallons UsedFuel CostRound Trip
LA to San Francisco380 mi15.2$53.20$106.40
NYC to Washington DC225 mi9.0$31.50$63.00
Chicago to Nashville470 mi18.8$65.80$131.60
Dallas to Houston240 mi9.6$33.60$67.20
Miami to Atlanta660 mi26.4$92.40$184.80
Seattle to Portland175 mi7.0$24.50$49.00

These estimates assume highway driving at 25 MPG. Add 15–20% for city driving segments and account for higher gas prices in California and the Northeast. For a personalized breakdown including tolls and passenger splits, use our gas trip calculator.

CO2 Emissions: What Your Driving Produces

Every gallon of gasoline burned produces 19.6 pounds of CO2. A 25 MPG car driven 12,000 miles/year emits about 9,408 lbs (4.3 metric tons) of CO2 annually. Improving from 25 to 35 MPG cuts emissions by 29%—saving 2,688 lbs of CO2 per year without changing your driving habits.

Diesel produces slightly more CO2 per gallon (22.4 lbs) but diesel engines typically get 20–35% better fuel economy, resulting in lower emissions per mile for many diesel vehicles. Hybrids cut per-mile emissions roughly in half compared to their gas-only counterparts.

4 Ways to Reduce Your Fuel Costs

  1. Maintain proper tire pressure. Under-inflated tires increase rolling resistance by 1–3%. At 25 MPG, that's an extra 3–9 gallons per year—$10–$30 wasted. Check pressure monthly and before long trips.
  2. Drive at steady speeds. Every 5 mph over 50 costs roughly $0.20 more per gallon burned. Cruise control on highways improves fuel economy by 7–14% compared to variable-speed driving.
  3. Remove excess weight. Every 100 pounds reduces fuel economy by roughly 1%. That ski rack you forgot to remove in June? It's costing you 2–8% in fuel economy from aerodynamic drag alone.
  4. Use the right fuel grade. If your car says "regular unleaded," premium is a waste. You're paying $0.50–$0.70 more per gallon for zero performance benefit in an engine designed for 87 octane.

To see how fuel fits into your total vehicle ownership costs, run the cost per mile calculator—it factors in insurance, depreciation, and maintenance on top of fuel. If you're shopping for a new car and want to know monthly payments, use the car payment calculator.