New weighting factor for plug-in hybrids in 2026: How emissions values and vehicle tax are affected
In 2026, a new weighting factor for plug-in hybrids will be introduced, providing more realistic emissions values and potentially affecting vehicle tax.
Starting in 2026, a new weighting factor for plug-in hybrid vehicles will be introduced in Sweden. The aim is to create a fairer and more realistic picture of how these vehicles are actually used in traffic—and thereby also provide a more accurate emissions value. In some cases, this may affect the vehicle tax for newly registered cars.
The new weighting model is being developed because plug-in hybrids are driven both on electricity and with an internal combustion engine. Until now, these two driving modes have been weighted according to a standardized method, but the EU has conducted an extensive study showing that the previous model no longer reflects real-world driving patterns. As a result, the formula will be revised at the turn of the year.
The updated model is intended to better reflect how much driving is done on electricity compared with the combustion engine, and it therefore affects the carbon dioxide value reported when a new vehicle is registered. This emissions value, in turn, forms the basis for the vehicle tax.
The adjustment is being made because previous calculations no longer represent actual driving behavior for many plug-in hybrids. The new model is based on an EU study analyzing how plug-in hybrids are actually used in practice.
Will the vehicle tax be affected?
Yes—but usually only marginally.
Vehicle tax is based on two components:
- a fixed base amount, and
- a carbon dioxide component that depends on how much the car emits above a certain threshold (111 g/km).
If the reported emission value increases due to the new weighting factor, the tax may be affected. However, the Swedish Transport Agency (Transportstyrelsen) assesses that most plug-in hybrids will continue to pay only the base amount of SEK 360 per year.
The change applies only to new cars registered from 2026 onwards. Plug-in hybrids that are already registered will not be affected.
Example: how vehicle tax may be calculated in 2026
Let’s assume that a plug-in hybrid, after applying the new weighting factor, receives an emissions value of: → 130 g CO₂/km in combined driving.
Step 1: Base Amount All petrol- and diesel-powered plug-in hybrids: SEK 360 per year (fixed base amount).
**For diesel plug-in hybrids, the following is added according to the Swedish Tax Agency: ** Fuel surcharge (CO₂-based) – 13.52 × the vehicle’s carbon dioxide emissions (g/km).
Environmental surcharge – SEK 250/year (for cars that became taxable for the first time after January 1, 2008).
If the plug-in hybrid is diesel-powered, the vehicle tax will be higher than for a comparable petrol car. This is because diesel vehicles have specific surcharges added on top of the base amount and the CO₂ component.
The purpose of these surcharges is to compensate for the fact that diesel cars generally produce different types of emissions than petrol cars, and that diesel fuel is taxed at a lower rate.
These surcharges are added to the sum of the base amount and the CO₂ component.
Step 2: Carbon Dioxide Component Calculated on emissions exceeding 111 g/km.
- 130 − 111 = 19 grams above the threshold
- 19 × SEK 22 = SEK 418
(SEK 22 per gram above 111 g/km, according to Transportstyrelsen’s tax formula)
Component | Amount | |
|---|---|---|
| Base Amount | SEK 360 | |
| CO₂ component | SEK 418 | |
| Total annual tax | SEK 778 |
In this example, the new plug-in hybrid would therefore incur an annual vehicle tax of SEK 778 after the malus period.
Please note: The example above shows the calculation of the base amount and the carbon dioxide component. For diesel-powered plug-in hybrids, a fuel surcharge and an environmental surcharge are added in accordance with the Swedish Tax Agency’s regulations, resulting in a higher total vehicle tax.
For vehicles using other types of fuel, see transportstyrelsen.se.
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