About
AAA's annual driving cost study: $0.70-1.20/mile typical. Many people forget depreciation (#1 cost). IRS standard mileage rate 2025: $0.67/mile. If you drive for business, deducting actual costs may beat standard rate. Track all expenses if so.
Formula
Frequently asked questions
How accurate is the Car Cost per Mile?
It applies the standard formula. Accuracy is limited only by your input precision. For decisions with material consequences (taxes, medical, legal, structural), use the result as a starting point and verify with a qualified professional in the relevant field.
Is the Car Cost per Mile free to use?
Yes. 100% free, no signup, no payment, no API key. The site is funded by display ads around the tool but not inside the calculation flow.
Are my inputs saved anywhere?
No. All inputs stay in your browser tab. Closing the tab discards them. The site uses Google Analytics for traffic measurement (anonymized) but the analytics never see what you type into the form.
Can I use the Car Cost per Mile on my phone?
Yes. The tool is responsive and tested on iOS Safari, Android Chrome, and major desktop browsers. Touch targets meet Apple's 44pt and Google's 48dp minimum.
Does the Car Cost per Mile work offline?
Yes. Once the page has loaded, it works without internet. The calculation runs in JavaScript on your device.
How do I report a bug or suggest improvement to the Car Cost per Mile?
Email hi@3tej.com with the URL of this page and a description of what you saw vs expected. We typically respond within 72 hours.
Can I share results from the Car Cost per Mile?
Take a screenshot or copy the output. The page doesn't generate shareable URLs for specific calculations - inputs stay in your browser only.
Why are the results different from another car cost per mile tool?
Most likely: different formula assumptions, different default values, different rounding rules, or different applicable rates. Check the methodology if both tools document it. Both can be valid for different scenarios.
Why is real-world MPG lower than the EPA rating?
EPA tests use specific city/highway/combined cycles in a controlled lab. Real driving includes more idling, more aggressive acceleration, A/C use, and higher speeds. Real-world MPG is typically 10-20% below the EPA combined rating.
How accurate is the trip computer in my car?
Modern trip computers are typically within ±5% of true MPG. Some cars consistently overestimate by ~3% (Toyota tends to be optimistic; Honda is closer). For accuracy, compare miles driven to gallons pumped over 3-4 fill-ups.
Does premium gas improve MPG?
Only if your engine is tuned for premium (most performance cars, some turbocharged engines). Otherwise no - the octane rating describes detonation resistance, not energy content. Regular gas in a car designed for regular is identical to premium in MPG.
Are EVs really cheaper to maintain?
Yes. No oil changes, no spark plugs, no timing belt, no exhaust, regenerative braking reduces brake pad wear. Average EV maintenance cost is ~40% lower than ICE. Tires wear slightly faster due to weight.
How long does an EV battery last?
Modern EV batteries warrant 8 years / 100,000 miles with most retaining 80%+ capacity. Real-world data through 2025 shows degradation around 2% per year - so 80% capacity at year 10.
Fuel economy units explained
| Unit | Definition | Used in |
|---|---|---|
| MPG (US) | Miles per US gallon | United States |
| MPG (UK / Imperial) | Miles per UK gallon | United Kingdom |
| km/L | Kilometers per liter | India, Japan, several Asian countries |
| L/100 km | Liters per 100 km (lower is better) | Europe, Canada, Australia, NZ |
| mi/kWh or kWh/100mi | Electric efficiency | US EV reporting |
| Wh/km | Watt-hours per km (EV, lower is better) | EU EV reporting |
US vs Imperial gallon
1 US gallon = 3.785 L. 1 UK gallon = 4.546 L. The Imperial gallon is ~20% larger, so MPG numbers in the UK look ~20% better than the same car measured in the US. A 40 MPG (UK) car is roughly 33 MPG (US).
Cost per mile / km
Total cost of vehicle ownership goes well beyond fuel. Average US sedan in 2026:
| Cost component | Annual cost (15,000 mi) | Per-mile |
|---|---|---|
| Fuel (gasoline, 28 MPG, $3.60/gal) | $1,929 | $0.129 |
| Insurance | $1,800 | $0.120 |
| Maintenance + tires | $1,200 | $0.080 |
| Depreciation (straight-line, 5 yr) | $5,000 | $0.333 |
| Registration + state fees | $200 | $0.013 |
| Total | $10,129 | $0.675 / mile |
That's ~$0.67/mile or ~$10,000/year for a typical car. EVs save ~$1,500/year on fuel + maintenance but have higher up-front cost and faster early depreciation.
How driving habits affect economy
- Speed: most cars peak around 50-55 mph (80-90 km/h). Going from 60 to 75 mph drops MPG by 15-25%.
- Acceleration: aggressive launches use 30%+ more fuel than gradual ones.
- Idling: zero MPG. Over 10 seconds of idle uses more fuel than restarting.
- Tire pressure: 10% under-inflation costs ~2% MPG and shortens tire life ~25%.
- Roof load: aerodynamic drag costs ~5 MPG at highway speed for a roof box; ~10% for a roof basket loaded with cargo.
- Cold starts: short trips (under 5 minutes) get the worst MPG because the engine never warms up.
EV vs gas: when does the math work?
The break-even depends on miles driven, fuel price, and electricity rate. Rough rules:
- Driving over 12,000 mi/year: EV wins on running cost.
- Home charging at $0.13/kWh: EV per-mile cost ~$0.04 vs $0.13 for gas.
- Purchase premium of $5,000-$10,000 for the EV: typically recouped in 4-7 years of average driving.
- Federal tax credits (US $7,500), state credits, and free public charging shift the math substantially.