Methodology & sources
Every default in our calculators is an editable estimate with a source and a check date. We don't hard-code figures that quietly go stale, and we never invent a number. All figures below were checked 2026-07-13.
Constants, sources and check dates
| Figure | Default | Source |
|---|---|---|
| Free Supercharging miles (referral) | 650 miles | Tesla UK — Refer and Earn |
| Inventory referral discount | £500 (inventory only) | Tesla UK — Refer and Earn |
| Home electricity (example default) | 24.5p/kWh | Ofgem price cap |
| EV night rate (example) | 7.5p/kWh | Typical smart EV tariff |
| Supercharger (member, peak) | 41p/kWh | Tesla Supercharging |
| Supercharger (non-member) | 53p/kWh | Tesla Supercharging |
| EV company-car BiK 2025/26 | 3% | GOV.UK company-car tax |
| EV company-car BiK 2026/27 | 4% | GOV.UK company-car tax |
| EV company-car BiK 2027/28 | 5% | GOV.UK company-car tax |
| EV chargepoint grant (max) | £350 | GOV.UK EV chargepoint grants |
| Home charger install (typical) | £800–£1500 | UK installer quotes |
Vehicle assumptions
Real-world efficiency figures are estimates from typical UK owner data and are deliberately conservative versus WLTP. Prices are indicative UK list prices — always confirm live at tesla.com/en_gb.
| Variant | Efficiency | WLTP range | Usable battery | List price |
|---|---|---|---|---|
| Model 3 (RWD) | 4.1 mi/kWh | 318 mi | 57.5 kWh | £39,990 |
| Model 3 Long Range AWD | 3.9 mi/kWh | 421 mi | 75 kWh | £44,990 |
| Model Y (RWD) | 3.7 mi/kWh | 311 mi | 60 kWh | £44,990 |
| Model Y Long Range AWD | 3.6 mi/kWh | 364 mi | 75 kWh | £51,990 |
What we deliberately exclude (because it's not true in the UK)
- No "free FSD" referral — FSD (Supervised) isn't road-legal/available in the UK yet.
- No Cybertruck referral — not sold or road-legal in the UK.
- No Tesla solar referral — Tesla doesn't retail solar panels in the UK.
- No Model S/X — removed from the UK line-up and referral programme in March 2026.