Defaults reflect early-2026 retail pricing. Verify MSRPs against tesla.com / kbb.com before relying on numbers for a real purchase. Real-world Tesla efficiency runs 10–20% below EPA in cold weather and at highway speeds.
How the math works:
- Charging losses: ~10% of grid energy is lost between wall and battery (real-world average across L2 and DC fast).
- Supercharger blended rate: $0.40/kWh is a national average; actual rate varies by location and time-of-day. Set this lower if you're in a cheap region or higher if peak-only.
- Federal EV credit: $7,500 in 2026 for qualifying new vehicles and buyers under income caps ($300k joint / $150k single). $4,000 for qualifying used vehicles under $25k MSRP.
- Maintenance: derived from the itemized schedule × per-vehicle complexity multiplier. Brake pads, fluid flushes, 12V battery, suspension wear all included.
- Depreciation: three-band composite curves (year 1, years 2–5, years 6–10) from Edmunds, KBB, and iSeeCars data.
- Residual value: subtracted from total TCO as "value you still own at end of period." A car with strong residual reduces effective lifetime cost.
- Interest: simple approximation = total payments over loan − principal. Real amortization would shift more cost into early years but yields the same total.
- Maintenance and insurance both compound annually at user-set rates.
What's NOT modeled: time value of money (discount rate), battery replacement (most Tesla packs last 200k+ miles), severe cold-weather range loss, state-by-state EV registration fees, public charging cost variance (non-Tesla DCFC often more expensive than Superchargers).
When Tesla wins: high annual mileage, low home electricity rates, tax credit eligible, financing at promo rates.
When ICE wins: low mileage (<8k/yr), expensive home electricity, no tax credit, heavy Supercharger use, planning to keep the car long enough to need a battery replacement out of warranty.