Car vs Bike Calculator (commute cost, CO₂ & calories)

Understanding the car vs bike commute calculator — concept and principle

This calculator compares commuting by car and by bicycle over a year: money saved, fuel not burned, tailpipe CO₂ avoided, and the calories you burn riding. It is useful when you are deciding whether to cycle to work, buying a commuter or e-bike, or putting numbers behind a workplace cycling scheme.

One commute, two ways: with the default inputs the result is $680.72 saved (after $150 of bike costs · 661 kg CO₂).

How it is calculated

Yearly distance (km) = one-way km × 2 × commuting days

Fuel (L) = yearly km × L/100 km ÷ 100

Car cost = fuel × fuel price + yearly km × other costs per km

Saving = car cost − bike costs per year

CO₂ (kg) = fuel (L) × 8.887 ÷ 3.785411784 for petrol (10.18 for diesel)

Calories (kcal) = MET × body weight (kg) × hours cycled, with hours = km ÷ speed

MET is 6.8 for an ordinary bike at commuting pace, 6.0 for an e-bike with light assistance and 4.0 with high assistance.

The principle

The car side is a simple running-cost model: you pay for the fuel you burn plus wear items that scale with distance. Tailpipe CO₂ follows directly from fuel burned, because almost all the carbon in petrol or diesel leaves the exhaust as CO₂; the US EPA puts this at 8,887 g per US gallon of petrol and 10,180 g of diesel. On the bike side, a MET (metabolic equivalent) is a multiple of resting energy use, and 1 MET is close to 1 kcal per kg per hour, which is why MET × kg × hours gives kilocalories.

Worked example

Default inputs: 8 km one way, 220 days, 8 L/100 km petrol at $1.70/L, other costs $0.10/km, bike costs $150/yr, 16 km/h, 75 kg rider, ordinary bike (6.8 MET).

Yearly distance = 8 × 2 × 220 = 3,520 km; fuel = 3,520 × 8 ÷ 100 = 281.6 L (shown as 282).
Car cost = 281.6 × 1.70 + 3,520 × 0.10 = 478.72 + 352 = $830.72.
Saving = 830.72 − 150 = $680.72.
CO₂ = 281.6 × 8.887 ÷ 3.785411784 ≈ 661 kg.
Hours = 3,520 ÷ 16 = 220 h; calories = 6.8 × 75 × 220 = 112,200 kcal; one trip = 6.8 × 75 × 0.5 h = 255 kcal, taking 30 min.

Each point is the calculator re-run with only “One-way commute (km)” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

One-way commute (km)	Money saved per year by cycling
2	$57.68
4	$265.36
6	$473.04
8	$680.72
10	$888.40
12	$1,096.08
16	$1,511.44

How to read the result

The saving is what changes in your pocket if you keep the car but leave it at home on commuting days. If cycling lets you sell the car, enter its yearly fixed costs divided by the km you drive as "other costs" to see the larger saving. The calorie figure is gross energy, including what you would burn at rest, so the extra burn is somewhat lower.

Common mistakes

Entering the round trip as the one-way distance, which doubles everything.
Using official fuel economy figures; city commuting usually uses more fuel.
Counting all calories as weight loss; the figure includes resting energy.
Forgetting days lost to rain, holidays or sickness.

Keep in mind: CO₂ is tailpipe only and leaves out fuel production and car manufacturing. Results are estimates for planning, not financial advice.

Frequently asked questions

How much CO₂ does a litre of petrol produce?

About 2.35 kg, from the EPA figure of 8,887 g per US gallon. Diesel gives about 2.69 kg per litre.

Does an e-bike still count as exercise?

Yes. The 2024 Compendium lists 6.0 MET with light assistance and 4.0 with high assistance, still well above rest.

Sources: US EPA, "Greenhouse Gas Emissions from a Typical Passenger Vehicle" · Herrmann S. D. et al. (2024), "2024 Adult Compendium of Physical Activities", J Sport Health Sci 13(1):6–12

Checked 9 Nov 2026. US EPA, “Greenhouse Gas Emissions from a Typical Passenger Vehicle” (8,887 g CO₂ per gallon of gasoline, 10,180 g per gallon of diesel); Herrmann S. D. et al. (2024), “2024 Adult Compendium of Physical Activities”, J Sport Health Sci 13(1):6–12 — codes 01011 (6.8 MET), 01084 (6.0) and 01088 (4.0); 1 US gallon = 3.785411784 L.

Your numbers