BYD Seal U vs BMW iX3 (UK): a £34,995 plug-in hybrid against a £53,250 electric BMW
Two family SUVs £18,255 apart that answer different questions. The BYD Seal U DM-i is a plug-in hybrid with 43 to 78 miles of electric range, a petrol engine for longer trips and six years of vehicle warranty. The BMW iX3 40 is a new-generation electric SUV with 360 to 395 miles WLTP and 300 kW rapid charging. We set out the UK figures, the warranty contracts and the Chinese owner record behind the BYD.
The verdict
These two SUVs are not really rivals on price: the BMW iX3 40 costs £53,250 on the road, £18,255 more than the entry BYD Seal U DM-i at £34,995, and still £13,255 more than the top Seal U Design at £39,995. What the extra money buys is a much better electric car: 360 to 395 miles of WLTP range from an 82.6 kWh battery, 300 kW rapid charging and a 2026 Euro NCAP five-star rating. The Seal U is a plug-in hybrid with 43 to 78 miles of electric range, an 18 kW rapid-charging cap and a petrol engine for everything beyond that. If your budget reaches the BMW and you can charge at home, the iX3 is the better car. If it does not, or you cannot charge reliably, the BYD is the sensible buy, with twice the vehicle warranty term, provided you accept its soft chassis and an unflattering Chinese owner record.
Buy the BYD Seal U if
Your budget tops out below £40,000, you cannot count on charging at home, or you mostly drive short local trips with the occasional long run. The Seal U DM-i costs £34,995 to £39,995, covers 43 to 78 miles on electricity depending on trim, then carries on as a petrol hybrid. It comes with 6 years or 93,750 miles of vehicle warranty. Go in knowing it accepts only 18 kW on a rapid charger, UK testers find the ride soft and unsettled, and its Chinese donor car scores 2.5 out of 5 on China's national complaint platform.
Buy the BMW iX3 if
You can charge at home, you cover long motorway distances and your budget stretches to £53,250. The iX3 40 is a battery-electric SUV with 360 to 395 miles of WLTP range and up to 300 kW DC charging, so long journeys need short stops rather than a hybrid engine. It holds a five-star Euro NCAP rating published in July 2026 that explicitly covers the right-hand-drive iX3 40. In exchange you pay £18,255 more than the entry Seal U and get a 3-year vehicle warranty, albeit with unlimited mileage.
| Dimension | BYD Seal U | BMW iX3 |
|---|---|---|
| UK entry price | BYD Seal U£34,995 (Boost)Better here | BMW iX3£53,250 (iX3 40) |
| Electric range | BYD Seal U43-78 miles WLTP (hybrid) | BMW iX3360-395 miles WLTPBetter here |
| DC charging speed | BYD Seal U18 kW maximum | BMW iX3300 kW maximumBetter here |
| Vehicle warranty | BYD Seal U6 years / 93,750 milesBetter here | BMW iX33 years, unlimited mileage |
| Battery warranty | BYD Seal U8 years / 155,350 milesBetter here | BMW iX38 years / 100,000 miles |
| Euro NCAP | BYD Seal U5 stars (2023 test) | BMW iX35 stars (2026 test) |
UK essentials: what each car is, and what it costs
The BYD Seal U DM-i is a Tucson-sized plug-in hybrid SUV sold in three trims, from £34,995 for the Boost to £39,995 for the all-wheel-drive Design. Every UK Seal U pairs a petrol engine with a battery and an electric motor, because BYD does not sell the fully electric Seal U in Britain. The BMW iX3 is the new-generation electric SUV BMW launched in 2026, and the iX3 40 added below the flagship iX3 50 xDrive brings the UK entry price down to £53,250 on the road. That still leaves £18,255 between the two cheapest versions, which makes this less a head-to-head than a question of budget and how you drive. The BMW's 82.6 kWh battery is more than three times the size of the larger Seal U pack, and it shows in the range figures.
| Attribute | BYD Seal U | BMW iX3 |
|---|---|---|
| UK entry price | BYD Seal U£34,995 on the road for the Boost, rising to £39,995 for the all-wheel-drive Design | BMW iX3£53,250 on the road for the iX3 40, BMW's cheaper rear-wheel-drive version, on sale in the UK from summer 2026 |
| electric range | BYD Seal U50 miles WLTP (Boost, 18.3 kWh), 78 miles (Comfort, 26.6 kWh), 43 miles (Design, 18.3 kWh) | BMW iX3360 to 395 miles WLTP on standard wheels; 331 to 392 miles on the heavier wheels of higher specs |
| powertrain | BYD Seal UDM-i plug-in hybrid only; the battery-electric Seal U sold in continental Europe is not offered in the UK | BMW iX3Battery electric; the iX3 40 is rear-wheel drive with 235 kW (320 hp) |
| battery capacity | BYD Seal U18.3 kWh on Boost and Design, 26.6 kWh on Comfort | BMW iX382.6 kWh, as listed by BMW UK without saying whether the figure is gross or usable |
Charging, company-car tax and what you actually pay
Charging is where the gap between the two cars is widest. The Seal U DM-i accepts a maximum of 18 kW on a DC rapid charger, which is low even by plug-in hybrid standards; What Car? gives 35 minutes from 30 to 80% on the smaller battery and 55 minutes on the larger one. The iX3 40 takes up to 300 kW, so a motorway top-up is a short stop. For company-car drivers, the Seal U works out at about £43 a month for a 20% taxpayer on comcar's figures, but only because its official CO2 is very low; leave the battery flat and testers have recorded about 35 mpg on the motorway. The BMW UK sources behind this page give no company-car tax figure or insurance group for the iX3, and we do not estimate either.
| Attribute | BYD Seal U | BMW iX3 |
|---|---|---|
| company-car tax | BYD Seal UAbout £43 a month for a 20% taxpayer in 2026/27, on CO2 of about 9 g/km and a P11D of about £36,825 | BMW iX3Not given in the BMW UK sources cited here; we do not estimate company-car tax (September 2026) |
| insurance group | BYD Seal UGroup 32 for Boost and Comfort, Group 40 for the Design | BMW iX3Not given in the BMW UK sources cited here (September 2026) |
| DC charging speed | BYD Seal U18 kW DC and 11 kW AC maximum; 30 to 80% takes 35 minutes (18.3 kWh) or 55 minutes (26.6 kWh) | BMW iX3300 kW DC maximum for the iX3 40; the pricier iX3 50 xDrive is rated at 400 kW |
Also noted
- BYD Seal U real-world economyAbout 35 mpg on the motorway once the battery is flat; the official 235 to 707 mpg needs regular charging
Warranty and safety: six years against three
The ownership contract is the BYD's clearest win. The Seal U DM-i carries 6 years or 93,750 miles of vehicle cover, twice the term of the BMW Electric Warranty, which runs for 3 years with unlimited mileage and roadside assistance from first registration. Both makers cover the high-voltage battery for 8 years: BMW to 100,000 miles, BYD to 155,350 miles under the extension it announced for Europe in January 2026. BYD's general UK policy page still lists 125,000 miles, so ask the dealer for the written, car-specific terms before you sign. On crash safety the two are level on stars. The Seal U's five-star Euro NCAP rating dates from a 2023 test of the electric version, extended to the plug-in hybrid in 2024; the iX3's five stars were published in July 2026 and apply to the right-hand-drive iX3 40.
| Attribute | BYD Seal U | BMW iX3 |
|---|---|---|
| vehicle warranty | BYD Seal U6 years or 93,750 miles | BMW iX33 years with unlimited mileage from first registration, including BMW Roadside Assistance |
| battery warranty | BYD Seal U8 years / 155,350 miles with a 70% capacity guarantee; BYD's general UK policy page still says 125,000 miles | BMW iX38 years or 100,000 miles, whichever comes first, under the BMW Electric Warranty |
| Euro NCAP rating | BYD Seal U5 stars, tested as the electric car in 2023 with the PHEV added in 2024: adult 90%, child 86%, VRU 83%, assist 77% | BMW iX35 stars, published 8 July 2026; tested as the iX3 50 xDrive, and the rating applies to the right-hand-drive iX3 40 |
China-side evidence
What Chinese owners say about the car the Seal U is built from
The UK Seal U DM-i is the export version of a car that has been on sale in China since 2021 as the BYD Song PLUS DM-i, and that donor car carries an owner record British buyers cannot easily read. On CheZhiWang, China's national vehicle complaint platform, the Song PLUS new-energy range scores 2.5 out of 5, with recurring reports of body electrical faults, steering and brake complaints, suspension and tyre wear, and water getting into the body. None of that is a prediction about a right-hand-drive car built to European requirements, but it is the strongest leading indicator available before UK cars have covered serious mileage. No equivalent owner-platform record for the BMW iX3 sits behind this comparison, so nothing of the kind is claimed about it.
Owner reports, complaint records and recall notices from the Chinese market, each with the source and the date we read it. Sample sizes are small; read them as signals, not survey results.
Who makes them, and will the brand still be here in six years?
A six-year warranty is only worth what the company behind it is worth. BYD Company Limited is the world's largest maker of new-energy vehicles and a Fortune Global 500 group, and it reported 2024 revenue of 777.1 billion yuan, up 23% year on year. In Britain it trades as BYD (U.K.) Co., Ltd., registration 08458577, and it had grown its retail network to 125 franchised dealerships across 38 retail partners by December 2025. BMW needs no such introduction here: its dealer and service network is one of the longest established in the UK, which matters for parts, courtesy cars and resale. Note that the iX3 on sale now is BMW's new-generation model, not the earlier X3-based iX3 sold until 2025, so reviews of the old car do not apply.
Living with the Seal U: the honest pros and cons
Our road-test evidence in this comparison is about the BYD, so this section is too. The Seal U DM-i is a value proposition and a good one on paper: a long electric range for a plug-in hybrid, a generous equipment list and a price that undercuts the Tucson, Sportage and Tiguan plug-in hybrids, let alone an electric BMW. UK testers are much less kind about the way it drives, criticising soft and unsettled suspension, light and vague steering and noticeable body lean on a B-road. The boot is smaller than its obvious rivals and towing is modest on the cheaper trims, so the case for the car rests on what it costs and how far it goes on a charge rather than on how it feels down a country lane.
Frequently asked questions
- Is the BYD Seal U cheaper than the BMW iX3?
- Yes, by a wide margin. The Seal U DM-i starts at £34,995 on the road and tops out at £39,995, while the BMW iX3 40 starts at £53,250. The entry BYD is £18,255 cheaper.
- Which has the better warranty?
- The BYD on term: 6 years or 93,750 miles against 3 years with unlimited mileage for the BMW. Both cover the battery for 8 years; BYD quotes 155,350 miles and BMW 100,000 miles. Confirm the BYD battery mileage for your car, as its general UK policy page still says 125,000 miles.
- Are the BYD Seal U and BMW iX3 safe?
- Both hold five-star Euro NCAP ratings. The Seal U was tested in 2023 as the electric car, with the plug-in hybrid added in 2024. The iX3 rating was published in July 2026 and applies to the right-hand-drive iX3 40.
- How far can the BYD Seal U DM-i go on electric power?
- The Seal U DM-i covers 43 to 78 miles WLTP on electricity depending on trim, then carries on as a petrol hybrid. The BMW iX3 40 is fully electric, with 360 to 395 miles WLTP.
- How much boot space does the BYD Seal U DM-i have?
- The Seal U DM-i has 425 litres with the seats up and 1,440 litres with them folded. That is smaller than the Tiguan, Sportage and Tucson plug-in hybrids.
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