Diesel Road Tax Calculator & RDE2 Surcharge Checker

The diesel tax calculator shows the first-year Vehicle Excise Duty (VED) for a diesel car first registered on or after 1 April 2017. A diesel that does not meet the Real Driving Emissions Step 2 standard (RDE2, which cars certified to Euro 6d meet) pays the first-year rate of the next CO2 band up. The calculator shows both the rate and how much of it is the diesel supplement.

Enter the car’s official CO2 figure and whether it meets RDE2, and the calculator shows the first-year rate and the supplement on its own. It does not look up your car.

Rates as of 3 November 2026: the GOV.UK vehicle tax rate tables in force from 1 April 2026.

How to use the diesel tax calculator

1. Enter the official CO2 figure in g/km from the brochure, price list or V5C box V.7. The tool opens at 135 g/km as an example, so replace it with your car’s figure.
2. Choose whether the car meets RDE2. Euro 6d cars do; Euro 6b, 6c and 6d-TEMP cars do not. If you are not sure, GOV.UK says to ask the manufacturer. The tool opens on “No / not sure”.
3. Read the first-year rate. It is the rate for the CO2 band your figure falls in, using the rate for a diesel that does or does not meet RDE2.
4. Read the extra amount, which is the diesel supplement compared with an RDE2 diesel or a petrol car with the same CO2.
5. Note the standard rate shown on the same card. From the second payment most cars pay the standard rate, so the supplement is only paid in the first year.

For example, at the default of 135 g/km with RDE2 not met, the first-year rate is £1,410, and the supplement over an RDE2 diesel is £850. At 115 g/km without RDE2, the rate is £560 and the supplement is £105. The tool reads the CO2 figure against the bands, so a figure of 130 g/km and one of 131 g/km fall in different bands and can give very different results.

How the diesel supplement works

The GOV.UK first-year table has a separate column for “all other diesel cars”. In practice each band in that column charges the next band’s petrol/RDE2 rate. Two exceptions: 0 g/km pays £10 in both columns, and over 255 g/km pays £5,690 in both, because there is no higher band.

Example: a non-RDE2 diesel with 135 g/km pays £1,410 in the first year instead of £560, a supplement of £850. At 115 g/km it pays £560 instead of £455, a supplement of £105.

The RDE2 diesel first-year supplement

The supplement is the difference between the “all other diesel” rate and the RDE2 rate for the same CO2 band. It is £0 for a car that meets RDE2. The largest supplement in the 2026/27 table is £1,430, in the 191 to 225 g/km band, where a non-RDE2 diesel pays £4,850 and an RDE2 diesel pays £3,420. In the 226 to 255 g/km band the supplement is £840.

Some bands have no supplement. The 0 g/km band pays £10 in both columns, and over 255 g/km pays £5,690 in both, because there is no higher band to move up to.

After the first year

The supplement is first-year only. From the second payment every car registered since April 2017 pays the standard rate (£200 a year in 2026/27), plus the £440 expensive car supplement for five years if the list price was over £40,000. The first-year supplement does not carry on into those later payments, so the tool shows it as a one-off amount.

Company cars

For company car tax, HMRC adds a 4% supplement to the appropriate percentage of a diesel company car, up to the maximum percentage for cars (37% in 2026/27). Since 2018/19 a diesel certified to RDE2 is exempt from it. Use a company car tax calculator for that part.

Clean Air Zones

RDE2 is a tax rule. London’s ULEZ and the Class D Clean Air Zones look at the Euro standard instead: any Euro 6 diesel meets them, RDE2 or not. The Euro standard on the V5C, not the RDE2 answer, is what decides whether a diesel is charged in those zones, so check that figure before you drive into one.

Frequently asked questions

What is the RDE2 diesel supplement?

A diesel car first registered from 1 April 2017 that does not meet RDE2 pays the first-year VED rate of the next CO2 band up. Depending on CO2 the extra is between £0 and £1,430 (2026/27 rates).

How do I know if my diesel meets RDE2?

Cars certified to Euro 6d meet it. The V5C may show the Euro standard; if not, ask the manufacturer.

Does the supplement apply to used diesels?

It is only part of the first-year rate. A used diesel taxed by its second or later keeper pays the standard rate like any other car registered since April 2017.

Are diesels charged in Clean Air Zones?

Only if they do not meet Euro 6. Euro 6 diesels meet the London ULEZ and Class D CAZ standards.

What is the supplement at the largest band?

The largest difference in the 2026/27 table is £1,430, in the 191 to 225 g/km band. A non-RDE2 diesel in that band pays £4,850 in the first year, against £3,420 for an RDE2 diesel.

What do I pay in the second year?

From the second payment, most cars registered since April 2017 pay the standard rate of £200 a year in 2026/27. The first-year supplement does not carry on, but the expensive car supplement can apply for years 2 to 6 if the list price was over £40,000.

Does this calculator check my car?

No. It works only from the CO2 figure and the RDE2 answer you type in. Confirm the Euro standard and the CO2 figure from your V5C or the manufacturer.

Sources (checked 3 November 2026): GOV.UK vehicle tax rate tables; HonestJohn: VED increases April 2026; HMRC policy paper: increasing the diesel supplement; HMRC manual EIM24705: appropriate percentage and diesel supplement.

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