Car vs Bike Calculator
Enter your commute distance, how often you ride, your car fuel economy, and gas price. The calculator shows how much money, CO2, and time you save by biking instead of driving, plus the equivalent trees planted and estimated life expectancy gained per year.
How the calculator works
Enter your one-way commute distance, how many days per week you would bike, and the number of working weeks per year. The car cost section uses your fuel economy and gas price to work out annual fuel expenditure. Toggle "full ownership cost" to swap in the IRS mileage rate (USD 0.67/mile in 2024), which folds in depreciation, insurance, and maintenance for a more complete picture. Parking fees you currently pay are added to the car side of the ledger. On the bike side, only annual maintenance is subtracted. The net savings is the difference.
CO2, trees, and your carbon footprint
The EPA states that burning one gallon of gasoline produces about 8,887 grams (8.9 kg) of CO2. The calculator multiplies the gallons you would have burned by this factor to find how much CO2 you avoid per year. One mature tree absorbs roughly 48 pounds (21.8 kg) of CO2 per year, so dividing your CO2 saving by that figure gives the number of tree-years your switch represents. For a 10-mile commute driven 5 days a week in a 28 MPG car, annual CO2 avoided is roughly 860 kg, equivalent to about 40 trees.
Health benefits: calories and life expectancy
Moderate cycling (about 12 mph / 19 km/h) burns roughly 500 calories per hour. The calculator uses this figure to estimate the annual calorie burn from cycling all your commute trips. A landmark Dutch study (de Hartog et al., 2010, published in Environmental Health Perspectives) estimated that the health benefit of cycling is so large that each minute spent cycling gains about one minute of life expectancy on average, even after accounting for accident risk and air-pollution exposure. This "1 for 1" rule is widely cited in transport health literature and is used here as a conservative estimate.
Time: is biking really slower?
For short urban commutes, cycling is often competitive with driving once you include time spent finding and walking to parking and warming up the engine. The calculator compares door-to-door speeds. If you set your car speed to a realistic urban average (20-30 mph including traffic lights and parking), you may be surprised how small the time gap is, and sometimes the bike wins. For commutes over 15 miles, the time gap becomes significant and an e-bike or partial transit connection may make the trip more practical.
Car vs bike: rule-of-thumb cost components
| Cost item | By car | By bike |
|---|---|---|
| Fuel / energy | $1,400-$2,200 | $0 |
| Parking | $0-$3,000 | $0 |
| Insurance | $1,000-$2,000 | $100-$300 |
| Maintenance | $800-$1,200 | $100-$200 |
| Depreciation | $2,000-$4,000 | $50-$150 |
| Total annual (estimated) | $5,000-$12,000 | $250-$650 |
Typical annual figures for a 10-mile one-way commute in the United States (2024). Actual costs vary by city, vehicle, and riding style.
Frequently asked questions
How is annual fuel savings calculated?
Annual miles driven equals one-way distance times 2 (round trip) times commute days per week times working weeks per year. Dividing by your MPG gives gallons consumed; multiplying by the gas price gives fuel cost. If you toggle the full-ownership-cost option, the IRS mileage rate (USD 0.67/mile) is used instead, capturing depreciation, insurance, and maintenance as well.
Does the calculator account for the cost of buying a bike?
The chart shows cumulative savings after subtracting a representative $800 bike purchase cost so you can see the payback period. The main savings figure uses only ongoing annual maintenance, since the purchase is a one-time cost. For a $800 bike saving $1,500/year, the payback is about 6-7 months.
What if I can only bike part of the year due to weather?
Reduce the "weeks commuted per year" input. For example, if you can bike 8 months of the year, set it to about 35 weeks instead of 48. The savings scale linearly with weeks, so the calculator handles any partial-year scenario.
How accurate is the life expectancy estimate?
The 1-minute-gained-per-minute-cycled figure comes from a peer-reviewed study by de Hartog et al. (2010) in Environmental Health Perspectives. It is an average across the population that balances the cardiovascular benefits of exercise against elevated accident and air-pollution risk. Individual results vary substantially based on route safety, existing health, and local air quality.
Should I use the fuel-only or full-ownership-cost option?
Fuel-only is useful if your car is already paid off and insured regardless of whether you drive it (many people keep their car for weekends). The full IRS rate is better if biking would let you downsize from two cars to one, or if you are deciding whether to buy a car at all. The IRS rate of USD 0.67/mile includes fuel, depreciation, insurance, and maintenance.
How many calories does cycling burn?
Moderate cycling at around 12 mph (19 km/h) burns roughly 400-600 calories per hour for an average adult. The calculator uses 500 kcal/hr as a midpoint. Heavier riders, hilly routes, and faster speeds increase calorie burn; lighter riders and flat terrain reduce it. The figure is a useful approximation for planning purposes, not a precise physiological measurement.