Show HN: A Calculator for Gas Costs and Road Trip Expenses
A precise digital tool for calculating fuel consumption, trip expenses, and per-person travel costs.
1Digital Fuel Cost Estimation
This tool provides precise fuel cost estimates for road trips by calculating distance against vehicle fuel economy. Users can input specific vehicle data or search EPA gasoline and diesel ratings from 1984 through 2027. The system allows for manual price adjustments or the use of current area averages for accurate budgeting.
2Metric and Imperial Flexibility
The calculator supports both US MPG and L/100 km units to accommodate different regional standards. While higher MPG indicates better efficiency, lower L/100 km values represent superior performance. Users can switch between these units seamlessly, ensuring that distance and fuel consumption data remain consistent regardless of the measurement system chosen for the trip.
3Calculating Trip Expenses
To determine fuel needs, the system divides total trip distance by the vehicle's fuel economy. For a 500-mile journey at 25 MPG, the requirement is 20 gallons. At a price of $4.27 per gallon, as recorded on October 26, 2026, this results in a total fuel cost of approximately $85.40 for the trip.
4Per-Mile Cost Analysis
Beyond simple fuel volume, the tool calculates the cost per mile by dividing the price per gallon by the vehicle's MPG. At 28 MPG and $4.27 per gallon, the fuel cost is approximately $0.15 per mile. This figure excludes additional ownership expenses like insurance, tire wear, vehicle maintenance, and long-term depreciation costs.
5Scaling for Long Distances
For a 1,000-mile drive, fuel costs fluctuate significantly based on vehicle efficiency. At 30 MPG, a driver consumes 33.3 gallons, costing roughly $142.33 at the $4.27 rate. Efficiency variations between 25 MPG and 35 MPG create a cost spread of over $48, highlighting the financial impact of vehicle fuel economy on long-distance travel.
6Monthly Budgeting Mechanics
Commuters can estimate monthly fuel expenditures by multiplying weekly mileage by 4.33 weeks. For a 250-mile weekly commute at 28 MPG, the monthly cost reaches $165.08 based on the $4.27 rate. This calculation helps users plan ahead, though actual results vary based on specific driving conditions, route choices, and individual vehicle performance.
7Sharing Trip Expenses
The tool facilitates cost splitting by dividing the total fuel amount by the number of passengers, including the driver. Users can add optional costs like tolls or parking fees to the total, which are then distributed per person. If specific toll data is unavailable, the system explicitly notes that tolls are not included.
8Data Accuracy and Limitations
Fuel prices are based on observed retail averages and vary by station or time. The calculator uses EPA combined ratings as a baseline, though actual city and highway efficiency often differ. Users are encouraged to verify their specific vehicle labels to ensure the most accurate financial projections for their planned road trips.
Original article: Hacker News: Show HN — Show HN: A Calculator for Gas Costs and Road Trip Expenses