Buying and running a car · calculate your comparison
Two cars.
All costs in view.
What does keeping your car cost compared with buying another? You can also compare two purchase quotes. Use the same period, mileage and costs from today for both options.
Two vehicles · one shared period
What is the total cost of your car?
Compare two purchase options, or keeping your current car with buying another. Start with your own documents or try a fictional example.
Calculations run in your browser. Entries are not sent to the website. Only when you choose “Add to my plan” is a snapshot kept in this browser tab. You can export or clear it in the planning sheet.
Calculation method and limitations
Total costs = purchase price + purchase-related costs − resale proceeds + interest and fees + new charging installation − its remaining value + other one-off costs − separate grants + energy and other running costs over the period.
Annual energy cost = kilometres ÷ 100 × consumption × energy price. With mixed charging, the electricity price is weighted by the shares of energy drawn. Annual averages are multiplied by the chosen number of years; totals for the full period are counted once.
All amounts are gross. Prices remain constant in this model; inflation, discounting and imputed interest on your own capital are excluded. Loan principal repayments are not added to the purchase price. Monthly costs are a calculated average, not a loan instalment or payment schedule. Values are rounded only for display.
When keeping your car, use its current market value minus its later residual value instead of a new purchase price. Do not count past purchase costs again. Today’s sale proceeds are not deducted again from the purchase option’s total costs. The separate purchase balance shows only part of the cash flow.
Leasing and plug-in hybrids are not covered. Residual value, consumption and repairs remain uncertain assumptions; this comparison is not a purchase recommendation.
Electricity consumption must include charging losses. Do not automatically treat solar electricity as free: for an existing PV system, foregone feed-in payments may be relevant, for example. Allocate new PV and battery investments separately. When using results from other calculators, use either the individual components or their total, never both.
Why the comparison period matters: The cost timeline in a simple illustrative example shows how upfront and annual costs interact. Its figures are technology-neutral and are not vehicle prices. For your vehicle comparison, use your own figures in the calculator, including the expected residual value.
Get prepared
Start with the figures you know.
Quote and costs
- Purchase price after discounts, delivery and registration.
- If financed: interest and fees for the chosen period.
- Insurance, vehicle tax, servicing, tyres and other costs.
- Any new charging installation and its allocated costs.
Use and assumptions
- The same ownership period and annual mileage for both cars.
- Consumption: including charging losses for an electric car.
- Your own electricity or fuel prices; if relevant, the shares of energy charged at home and in public.
- Expected resale value at the end, with sources and uncertainties.
How to enter a real purchase quote correctly
Use the gross purchase price of the specific vehicle quoted. A monthly payment, a vehicle value used for a lease or a recommended retail price is not a substitute.
- Conditions: Does the price depend on a grant, financing, a trade-in or belonging to a particular customer group? Record unconfirmed conditions in your notes and also calculate without that benefit.
- Discounts and grants: Do not enter an amount already deducted as a separate grant again. Ask for the invoice amount, any reimbursement and your own contribution to be shown separately.
- Delivery and registration: Mark costs as “Already included” only if they are explicitly included elsewhere. Leave missing figures open or label them as your own assumptions.
- Comparability: Also check equipment, vehicle condition, battery size, delivery date and suitability for everyday use. The same model name does not mean the same specification.
- Consumption and residual value: Distinguish figures in the quote from your own usage assumptions. Do not add charging losses again if they are already included in electricity consumption; do not treat an estimated resale value as a guaranteed amount.
Note the quote number, date accessed, source and outstanding questions. If price information conflicts, request a complete written quote.
Unknown figures stay open. The calculator then shows known cost categories and the information still needed. The full comparison appears once all costs have been recorded.
Check possible electric car funding: Electric car funding: eligibility and application steps · Official programme information from the Federal Environment Ministry →. Count the grant only once. If it has already been deducted from the purchase price, do not enter it again in the grant field. If funding is still uncertain, also calculate without it. The funding programme may also cover leasing; this calculator compares purchase options and does not model a lease contract.
When keeping your car: record its current sale value, expected residual value after the same period and upcoming repairs. For an existing loan, count only future interest and fees as costs. Outstanding principal affects cash flow separately.
What does the comparison tell you?
How is this different from the charging cost calculator?
The vehicle comparison also includes purchase costs, residual value, financing and other running costs. The charging cost calculator compares two charging options for the same journeys. For additional fees, use the public charging tariff comparison.
Are the monthly costs my monthly payment?
No. The figure spreads the total costs mathematically across all months of the ownership period. The purchase price and resale proceeds occur at different times; a loan payment also includes principal repayment. You need a separate payment schedule to plan your cash flow.
How reliable is the result?
It applies to the assumptions entered. Resale value, energy prices and repairs may turn out differently. Use “What changes the result?” to test individual changes without overwriting your original comparison. The calculator does not give a universal mileage threshold above which one type of vehicle always pays off.
Can I compare keeping my car with buying another?
Yes. Choose “Keep my car or buy another”. Vehicle A is your current car. Enter its current market value instead of the original purchase price. Past costs are not counted again, and today’s sale proceeds are not deducted again from the purchase option’s total costs. Test other residual values and repair assumptions. Leasing and plug-in hybrids are not covered.
Which part would you like to explore further?
Calculation model and technical reference
The cost structure covers depreciation, energy, fixed costs, servicing and tyres. One technical reference is the ADAC car cost overview, spring/summer 2026 (PDF). The calculator uses your figures and an explicitly fictional example; it does not import vehicle prices or residual-value forecasts from ADAC.
The formula and limitations are shown directly below the calculator. Model version: September 2026.