Public Transport Savings Calculator
Commuting by public transit instead of driving can save thousands of dollars per year once you account for fuel, vehicle wear, and parking. This calculator compares the full annual cost of driving to work with the cost of a monthly transit pass, using the AAA 2023 average of $0.61 per mile as the default car cost. The AAA figure is comprehensive: it includes fuel, maintenance, tyres, insurance, registration fees, and depreciation, giving a true cost of motoring rather than fuel alone. Parking costs are added separately because they vary enormously by city and workplace. Annual CO2 savings use the EPA per-mile emission factor of 0.356 kg of CO2 equivalent for an average passenger car. Switching commutes from car to transit does not just save money. The American Public Transportation Association reports that public transit produces significantly lower greenhouse gas emissions per passenger-mile than single-occupancy vehicles. Enter your commute details below to see your personalised annual savings and CO2 reduction from making the switch.
Annual savings switching to transit: -- and CO2 reduction: -- kg/year.
How the transit savings calculation works
The calculation compares the full annual cost of driving a round-trip commute (including parking) against the annual cost of a monthly transit pass.
Annual driving distance = one_way_miles × 2 × commute_days
Annual car cost ($) = annual_miles × car_cost_per_mile
Annual parking ($) = parking_per_day × commute_days
Total annual car cost ($) = annual_car_cost + annual_parking
Annual transit cost ($) = transit_monthly × 12
Annual savings ($) = total_car_cost - annual_transit_cost
CO2 reduction (kg) = annual_miles × 0.356
Worked example
15 miles one-way, 250 days/year, $0.61/mile, $100/month transit, $10/day parking:
- Annual distance = 15 × 2 × 250 = 7,500 miles
- Annual car cost = 7,500 × $0.61 = $4,575.00
- Annual parking = $10 × 250 = $2,500.00
- Total car cost = $4,575 + $2,500 = $7,075.00
- Annual transit = $100 × 12 = $1,200.00
- Annual savings = $7,075 - $1,200 = $5,875.00
- CO2 reduction = 7,500 × 0.356 = 2,670.00 kg
Monthly transit pass costs across major US cities
| City / Transit Agency | Unlimited Monthly Pass (approx.) |
|---|---|
| New York City (MTA) | $132 |
| Chicago (CTA) | $105 |
| Los Angeles (Metro) | $100 |
| Washington DC (WMATA) | varies by zone, $100 to $230 |
| Boston (MBTA) | $90 |
| San Francisco (SFMTA) | $81 |
| Seattle (King County Metro) | $99 to $140 |
Verify current fares at your local transit agency's website. Prices are approximate and subject to change.
Public transport savings calculator: frequently asked questions
How does this calculator estimate car commute costs?
This calculator uses AAA's 2023 Your Driving Costs study, which calculates the total cost of car ownership per mile including fuel, maintenance, tyres, insurance, registration fees, and depreciation. The 2023 AAA average is $0.61 per mile for a mid-size sedan. This is a comprehensive ownership cost figure, not just fuel. You can adjust the per-mile cost to match your vehicle's actual cost or to use a fuel-only figure if you prefer to separate ownership costs.
Does switching to transit eliminate my car costs entirely?
Only if you give up your car entirely. Many households keep a car for non-commute trips and gain the transit savings on top of reduced car use. If you eliminate the car, you save the full ownership cost. If you keep the car, the savings shown here represent the fuel and wear costs avoided on commute trips, plus parking. The fixed costs of insurance and loan payments continue regardless of how much you drive.
What CO2 emission factor is used for driving?
This calculator uses the EPA figure of 0.356 kg of CO2 equivalent per mile for an average passenger car, from the EPA's GHG Equivalencies Calculator. This is a per-mile figure that blends fuel combustion CO2 with upstream emissions. For a more precise figure based on your specific vehicle's fuel economy, you can calculate it as: gallons per mile = 1 / MPG, then multiply by 8.89 kg CO2 per gallon (EPA).
How accurate is the $0.61 per mile AAA figure?
AAA's cost is a national average across vehicle sizes and ages. Your actual cost will differ based on your vehicle type, age, loan balance, insurance rate, and local fuel prices. Smaller, older, paid-off vehicles cost significantly less per mile. A fuel-only estimate for a 30 MPG car at $3.50/gallon is about $0.117 per mile. Entering your own per-mile figure gives you a more personalised result.
What transit costs should I include in the monthly transit pass field?
Enter the actual monthly cost of your transit pass or average monthly transit spending. Most cities offer monthly passes that reduce the per-trip cost significantly. In some cities, employers offer pre-tax commuter benefits that further reduce the after-tax cost of transit passes. Check your employer's benefits package for transit spending accounts, which allow you to pay for transit passes with pre-tax dollars up to IRS limits.
Official sources
- AAA Your Driving Costs 2023: newsroom.aaa.com/auto/your-driving-costs.
- EPA GHG Equivalencies Calculator: epa.gov/energy/greenhouse-gas-equivalencies-calculator.
- American Public Transportation Association: apta.com/research-technical-resources/transit-statistics.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology. General information only, not financial advice.