Automotive calculators give car buyers, owners, and enthusiasts the numbers that dealerships rarely volunteer: the true cost per mile to run your vehicle, how much of its value evaporates in year one, whether a used car’s mileage is plausible for its age, and exactly how a wheel offset change affects your fender clearance and steering feel. Every calculator here covers the formula, the benchmark, and the specific mistake that costs people money.
Buying and owning a car involves three categories of numbers that affect real financial outcomes: ownership cost (fuel, depreciation, maintenance), purchase intelligence (is this used car’s mileage legitimate, is the price fair for the condition), and modification safety (will these wheels actually fit without rubbing). Most car buyers get one or two of these right. The fuel economy calculator, depreciation calculator, odometer fraud calculator, and wheel offset calculator cover all four dimensions together — because the decisions are connected. A car with artificially low mileage is priced higher, depreciates differently, and its true cost per mile changes completely.
The EPA combined MPG rating is a laboratory figure. Real-world fuel economy is typically 15–20% lower due to aggressive acceleration, air conditioning, highway speeds above 55 mph, cold weather, and cargo weight. The Department of Energy research shows fuel economy drops approximately 1–2% for every 100 lbs of additional weight, and AC usage can cut efficiency by up to 25% in hot weather. Highway cruising speed matters more than most drivers realise: efficiency peaks at approximately 55 mph for most gas vehicles and drops steadily above it due to aerodynamic drag increasing with the square of speed.
The average new vehicle loses 15–25% of its purchase price the moment it is driven off the lot — before the first service interval. This first-year drop is the largest single depreciation event in a vehicle’s life and is the primary financial argument for buying a vehicle that is 1–3 years old. A $40,000 new vehicle typically retains $30,000–$34,000 in value after year one — meaning a buyer of a 1-year-old equivalent vehicle saves $6,000–$10,000 for a vehicle with 12,000–18,000 miles. After year 5, most vehicles retain 35–45% of MSRP on average, with significant variation by brand and model. Toyota and Lexus consistently lead 5-year retention at 55–65%. Certain European luxury brands trail at 28–38%.
"ET" on a wheel specification stands for Einpresstiefe — German for "insertion depth." It measures in millimetres from the wheel’s hub mounting surface to its centreline. Nearly every wheel offset calculator online uses ET notation without ever explaining this. Positive ET means the mounting surface is toward the outside of the wheel, tucking it toward the suspension. Negative ET pushes the wheel outward past the fender. Changing ET by more than 15–20mm from factory specification affects more than aesthetics: it shifts the scrub radius (changing steering feel and return-to-centre behaviour), alters wheel bearing load distribution (accelerating wear if extreme), and can interfere with ABS wheel speed sensor alignment on modern vehicles. Always check clearances at full steering lock and full suspension droop before committing.
Federal EV tax credit expired — critical update for 2026 vehicle buyers: The federal EV tax credit (Section 30D, up to $7,500 for new EVs) expired September 30, 2025 under Public Law 119-21. It is not available for vehicles purchased in 2026. If you purchased a qualifying EV before that date, you may still claim it on your 2025 tax return. Many states still offer separate EV rebates and incentives that remain active — check your state’s energy office before purchase. Without the federal credit, the break-even calculation between EV and comparable gas vehicle shifts by $3,750–$7,500 and typically extends break-even by 1–2 years at average annual mileage.
Industry averages across all vehicle types. Individual models vary significantly. Brands with the strongest retention (Toyota, Lexus, Jeep Wrangler, Honda) outperform by 15–20 percentage points. Luxury European brands underperform by 10–20 percentage points.
| Year | Avg % MSRP Retained | $ Remaining ($40k car) | Key Insight |
|---|---|---|---|
| New (off lot) | 75 – 85% | $30,000 – $34,000 | 15-25% lost immediately at purchase |
| 1 year | 68 – 78% | $27,200 – $31,200 | Biggest buying opportunity for used |
| 2 years | 60 – 70% | $24,000 – $28,000 | Warranty often still active |
| 3 years | 53 – 63% | $21,200 – $25,200 | CPO programs available, big savings |
| 5 years | 35 – 45% | $14,000 – $18,000 | Average retention benchmark |
| 7 years | 25 – 35% | $10,000 – $14,000 | Major repairs more likely |
| 10 years | 15 – 25% | $6,000 – $10,000 | Best value per mile if reliable |
Based on FHWA average annual mileage of 15,000 miles per year for US drivers. Vehicles with claimed mileage more than 30% below these figures warrant extra scrutiny — either they had an unusual ownership history or odometer fraud may have occurred.
| Vehicle Age | Expected Mileage (15k/yr) | Suspicion Threshold (<30%) | Status |
|---|---|---|---|
| 1 year | 15,000 miles | Under 10,500 | Verify ownership history |
| 2 years | 30,000 miles | Under 21,000 | Check service records |
| 3 years | 45,000 miles | Under 31,500 | Physical wear inspection critical |
| 5 years | 75,000 miles | Under 52,500 | High-risk if priced at market |
| 7 years | 105,000 miles | Under 73,500 | VIN check + pre-purchase inspection |
| 10 years | 150,000 miles | Under 105,000 | Check all physical wear indicators |
Combined city/highway estimates. Real-world MPG is typically 15–20% lower. If your actual MPG is more than 20% below EPA estimate, check tire pressure, air filter, and driving habits.
| Vehicle Class | EPA Combined MPG Range | L/100km | Cost/Mile at $3.50/gal |
|---|---|---|---|
| Compact car (gas) | 32 – 40 MPG | 5.9 – 7.4 | $0.088 – $0.109 |
| Midsize sedan (gas) | 28 – 35 MPG | 6.7 – 8.4 | $0.100 – $0.125 |
| Small SUV / crossover | 27 – 34 MPG | 6.9 – 8.7 | $0.103 – $0.130 |
| Midsize SUV | 22 – 28 MPG | 8.4 – 10.7 | $0.125 – $0.159 |
| Full-size pickup truck | 18 – 24 MPG | 9.8 – 13.1 | $0.146 – $0.194 |
| Plug-in hybrid (gas mode) | 35 – 50 MPGe | 4.7 – 6.7 | $0.070 – $0.100 |
| Best conventional gas 2026 | 48 – 54 MPG | 4.4 – 4.9 | $0.065 – $0.073 |
Odometer fraud at record levels in 2026 — 2.45 million US vehicles affected: Carfax’s 2026 report identifies 2.45 million vehicles currently on US roads with rolled-back odometers — a 14% increase year-over-year. Digital odometers can be rolled back in minutes with commercial tools that cost under $100 online. The most reliable physical fraud indicators are components with no digital counterpart: steering wheel leather wear, brake pedal rubber wear-through, driver’s seat bolster compression, and door sill scuff marks. If a car shows 30,000 miles but the steering wheel leather is cracked and the brake pedal rubber is deeply grooved, the odometer is lying. Oil change stickers on the windshield are another underused resource — one reading "87,500 miles / next service 91,000" with an odometer showing 54,000 miles tells you everything. Always run the VIN through NHTSA’s free vehiclehistory.gov database and pull a Carfax or AutoCheck report before any used car purchase.
Start with the fuel economy calculator using your actual fill-up data — not the EPA estimate. The EPA number is a useful benchmark, but your personal driving pattern, local climate, and vehicle condition determine your real cost. At 15,000 miles per year, the difference between 25 MPG and 35 MPG at $3.50/gallon is $600 per year in fuel costs alone. Over 5 years, that is $3,000 — more than the premium many buyers pay to choose the more efficient vehicle. Add depreciation using the depreciation calculator to see total ownership cost. Depreciation typically represents 35–45% of total ownership cost over 5 years — larger than fuel, maintenance, and insurance combined for most vehicles.
Run the odometer fraud calculator first: enter the vehicle’s age and claimed mileage to see how it compares to the FHWA 15,000 miles/year baseline. A 5-year-old car with 35,000 miles (7,000/year) is either a genuine low-mileage vehicle (fleet car, secondary vehicle, elderly owner with documented history) or potentially fraudulent. Verify with a Carfax report, check physical wear indicators, and budget for a $100–$200 independent pre-purchase inspection from a mechanic who has no commercial relationship with the seller. The inspection pays for itself if it catches one hidden problem. Then use the depreciation calculator to verify the asking price reflects the vehicle’s actual position on the depreciation curve relative to MSRP and current market.
Use the wheel offset calculator to compare your current ET specification against the new wheels before purchasing. Enter your current wheel width and ET, then the new wheel width and ET, and the calculator shows inner clearance change (suspension side) and outer position change (fender side). The safe range for most passenger cars is ±15mm from factory ET. For trucks and SUVs with larger wheel wells, ±25mm is typically manageable with a physical test-fit. Always test at full steering lock in both directions and full suspension compression before declaring a fitment safe — clearances that work at straight-ahead static may rub at the extremes of suspension travel and steering angle.
Three decisions produce the most preventable automotive financial losses. First: buying new when buying 1–3 years used saves 15–35% of vehicle cost with minimal difference in reliability — especially on vehicles with strong reliability records where the risk of the used purchase is low. Second: trusting the odometer without physical verification — 2.45 million US vehicles have fraudulent readings in 2026, and digital odometers provide no more security than mechanical ones. Third: choosing wheels based on the look without calculating the ET change and its effect on handling, bearing load, and legal fender coverage — an aggressive negative-offset fitment that causes tires to poke past the fenders is illegal in many jurisdictions and void-warranty territory on most manufacturer warranties.
Most used tools across all 14 categories