BYD Seal U DM-i vs Lexus NX 450h+: which is cheaper to run?
Both are plug-in hybrids; both look attractive on the brochure. The interesting question is how much one costs you over a real year of UK driving — at your tariff, your mileage and your charging habits. Here's the honest side-by-side at typical UK assumptions.
| Spec | BYD Seal U DM-i | Lexus NX 450h+ |
|---|---|---|
| Battery | 18.3 kWh | 18.1 kWh |
| WLTP electric range | 50 mi | 40 mi |
| WLTP combined MPG | 141 mpg | 282 mpg |
| Real-world petrol-only MPG | 45 mpg | 46 mpg |
Annual running cost (10,000 mi · 60% on battery)
| Cost | BYD Seal U DM-i | Lexus NX 450h+ |
|---|---|---|
| Battery £/mile | 2.3p | 2.3p |
| Petrol £/mile | 15.7p | 15.4p |
| Blended £/mile | 7.7p | 7.6p |
| Annual cost | £770 | £756 |
| Break-even fuel price | £0.23/L | £0.24/L |
Annual running cost difference
£14
The Lexus NX 450h+ is roughly £14 cheaper a year (2%) at these assumptions.
The honest take. On running costs alone, the Lexus NX 450h+ is the cheaper of the two at typical UK numbers. But running cost is only one variable — purchase price, finance, tax, insurance and depreciation usually swamp it. Use the free calculator below to plug in your own annual mileage, your home electricity tariff, and what % of your driving you'll realistically do on battery. Two minutes and you'll know which car is actually cheaper for your driving.
Run your own numbers — both PHEVs pre-loaded
Calculator opens with the BYD Seal U DM-i and Lexus NX 450h+ side-by-side · adjust to your miles and tariff · save your comparison free