Auto calculators
Loan, lease-vs-buy, MPG, fuel cost, and total-cost-of-ownership math.
All auto tools
16 tools, each runs locally in your browser. Click any card to open it.
Auto Loan Calculator computes monthly payment, total interest from vehicle price, down payment, trade-in, rate, term. …
Auto Loan Payoff vs Invest computes monthly payment, total interest from vehicle price, down payment, trade-in, rate, …
Estimate gallons used and fuel cost for a day on the water by horsepower and engine hours.
20% down · 4-yr loan · ≤10% gross income for total transport. Skip if violates.
Car Depreciation Calculator takes vehicle price, down payment, rate, term and returns the matching car depreciation re…
Car Loan EMI computes monthly payment, total interest paid from loan amount, interest rate, term. Runs entirely in you…
Estimate real-world EV range with weather and driving style adjustments. See actual miles you can drive.
Lease vs Buy Car Calculator takes vehicle price, down payment, rate, term and returns the matching lease vs buy car re…
lease vs buy car, lease or buy, leasing vs buying a car, car lease comparison, lease vs finance lease vs buy: lower mo…
MPG / Fuel Economy Calculator takes vehicle price, down payment, rate, term and returns the matching mpg / fuel econom…
Plan your drive budget. Tally fuel, lodging, and food into a single trip total and split per traveler.
RV MPG + Fuel Cost Calculator takes vehicle price, down payment, rate, term and returns the matching rv mpg + fuel cos…
A Tire Pressure Converter converts data from one format to another using a deterministic mapping. It parses the input,…
Switching tires? Bigger = speedo reads slow. Smaller = reads fast.
Calculate how long it takes to charge your electric vehicle. Compare Level 1, Level 2, and DC fast charging times.
5-year total cost of owning a vehicle. Includes purchase, financing, fuel, insurance, maintenance, depreciation, and r…
About auto
Auto calculators cover the buying, financing, and ownership math you run before signing at the dealership or pumping gas: auto loan EMI / payment with trade-in and down payment, lease vs buy break-even, MPG conversion (US gallons to L/100km), fuel cost per mile / km, EV charging cost at home vs DC fast charger, total cost of ownership over 5 years, depreciation curves by make and model, and tire size conversion (P-metric to LT, plus the speedometer error from a non-OE size).
Use these tools when deciding 36 vs 60 month financing at the same rate, picking between a $35k purchase and a $400/month lease, computing the fuel-cost gap between a hybrid and an ICE on your commute, modeling 5-year cost on an EV vs equivalent ICE including charging, or sanity-checking the speedometer error from going to a +20 sidewall.
Sources: KBB and Edmunds for depreciation curves, EIA for gasoline price data, EPA for MPG ratings, manufacturer specs for tire dimensions. Defaults to US conventions; toggle metric and imperial per tool.
Common use cases
Real scenarios where the auto calculators in this category earn their keep.
Auto loan payment
Compute monthly payment given price, down payment, trade-in, APR, and term. The auto loan tool also outputs total interest paid and the running balance over the loan.
Lease vs buy break-even
Compare the total cash outflow of a 3-year lease (down + 36 payments + disposition) vs buying with a loan and selling at 36 months (down + 36 payments + sale - residual). Accounts for opportunity cost on capital.
MPG / fuel cost on a commute
Annual fuel cost = (miles / mpg) × $/gallon. Compare two vehicles to see the dollar gap of an upgrade.
EV charging cost
Cost per mile = (kWh / 100 mi) × $/kWh. Home overnight ($0.10-0.15/kWh) is typically 1/3 the cost of DC fast ($0.30-0.50/kWh). The EV tool models a mix.
Tire size and speedometer error
Replacing the OE tire with a different sidewall changes revolutions per mile, which shifts the speedometer reading. The tire calculator outputs the percentage error so you can plan for re-calibration.
Key terms
Glossary for the formulas and conventions these tools use.
- APR
- Annual Percentage Rate. The nominal annualised cost of an auto loan, including fees folded into the financing. Used in the EMI formula.
- Money factor
- Lease equivalent of an interest rate. Multiply by 2,400 to get an approximate APR. Banks quote leases by money factor + residual.
- Residual value
- The leasing bank's predicted vehicle value at lease end. Higher residual = lower depreciation cost during the lease term = lower monthly.
- MPGe
- Miles per gallon equivalent for EVs. EPA assumes 33.7 kWh of electricity is energy-equivalent to 1 gallon of gasoline.
- L/100km
- Liters per 100 kilometers. Inverse of MPG, used in most countries outside the US. Lower = more efficient.
- Total cost of ownership
- Purchase + financing interest + fuel/electricity + maintenance + insurance + depreciation - resale. Typical 5-year window.
- Sidewall aspect ratio
- Tire sidewall height as percentage of section width. 225/45R17 = sidewall is 45% of 225mm. Changing aspect ratio changes the rolling diameter.
Frequently asked questions
Short answers to the most common auto questions.