RealCost Tool
Road Tax Calculator UK
Use this Road Tax Calculator UK to estimate how much vehicle tax could cost over the time you plan to keep a car.
Enter the relevant first-year tax rate, standard annual tax, ownership length and any expensive car supplement to estimate the total road tax cost, average yearly cost and monthly equivalent.
Estimate ownership cost
See the road tax cost across the number of years you plan to keep the car.
Include supplement costs
Add any expensive car supplement so higher-list-price cars do not look cheaper than they really are.
Monthly budgeting view
Turn road tax into an average monthly figure for easier car ownership budgeting.
Calculate your road tax cost
Enter how long you plan to keep the car, the first-year tax rate, the standard annual rate and any expensive car supplement. The calculator will estimate your total road tax cost and monthly equivalent.
This is a road tax budgeting calculator, not an official DVLA or VED checker. Always confirm the exact tax rate for a specific vehicle using official vehicle details, registration date and current rules.
Road tax can catch buyers out
Road tax is not always just one simple yearly figure. The first-year rate, standard annual rate and expensive car supplement can all affect the real cost, especially when comparing newer cars, higher-list-price cars and cars with different emissions figures.
RealCost note: This calculator does not automatically work out an official road tax band from CO₂. Enter the relevant first-year rate, standard annual rate and any supplement after checking the vehicle’s official details. For the full ownership picture, use the Car Cost Calculator UK. If you are comparing fuel types, also check the Electric vs Petrol Running Cost Calculator.
What the calculator includes
The calculator uses practical inputs to estimate road tax across the time you plan to keep the car.
Years you plan to keep the car
How long you want to estimate road tax for.
Expensive car supplement per year
Any additional yearly supplement that applies to the vehicle. Enter £0 if it does not apply.
CO₂ emissions
The emissions figure entered for reference. The calculator does not use this to automatically find a tax band.
Years supplement applies
How many years of your ownership estimate include the expensive car supplement.
First-year tax rate
The first-year road tax rate for the car.
Standard annual tax
The yearly rate after the first year.
What the results tell you
The results show first-year cost, yearly cost after the first year, total ownership cost and average monthly cost.
Estimated first year road tax
The first-year tax rate plus any expensive car supplement you entered.
Annual road tax after first year
The standard yearly road tax after the first year, including any supplement entered.
Base road tax over ownership
The estimated road tax over the ownership period before any expensive car supplement.
Supplement over ownership
The total extra cost from the expensive car supplement over the years entered.
Total road tax over ownership
The estimated total road tax cost over the period you plan to keep the car.
Average monthly road tax
The total road tax cost averaged into a monthly ownership figure.
Example road tax result
This example uses a car kept for 3 years, with £0 expensive car supplement, 0g/km CO₂ entered, £10 first-year tax and £200 standard annual tax.
Years kept
3
CO₂ entered
0g/km
First-year rate
£10
Standard annual rate
£200
Estimated first year
£10
Annual after first year
£200
Base over ownership
£410
Supplement total
£0
Estimated ownership total
£410
Average monthly
£11.39
Average yearly
£136.67
What this means: The average yearly cost can differ from the standard annual rate because the first-year rate and any supplement change the ownership-period total.
How to use the calculator properly
Use official vehicle details first, then use this calculator to understand the cost over your ownership period.
Important: For used cars, check the car’s registration date, fuel type, CO₂ figure and official tax information before entering the rates. For newer or higher-list-price cars, check whether the expensive car supplement applies.
When this calculator is most useful
Use it when road tax needs to be included in a wider car ownership decision, not just checked as one annual number.
Road tax is not the full cost
A low road tax figure does not automatically make a car cheap to own.
Value loss can be much larger than road tax.
A cheap-tax car can still be expensive to insure.
Mileage and efficiency can matter more than road tax.
Servicing, tyres, MOTs and repairs still need budgeting.
Some newer or higher-list-price cars can cost more than expected.
Cars with similar emissions can be taxed differently depending on when they were registered.
What to calculate next
Use these tools to connect road tax to the wider ownership decision.
Car Cost Calculator UK
Estimate full ownership cost including tax, depreciation, insurance and running costs.
Car Depreciation Calculator UK
Check whether value loss is bigger than the tax difference.
Car Insurance Cost Calculator UK
Compare road tax with insurance cost in your monthly budget.
Car Maintenance Cost Calculator UK
Add servicing, MOT, tyres and repair allowance into the ownership picture.
Fuel Cost Per Mile Calculator UK
Compare tax against the fuel cost of actually using the car.
Electric vs Petrol Running Cost Calculator
Compare petrol and electric running costs before choosing your next car.
Related ownership guides
Use these pages when road tax is part of a bigger car ownership decision.
Average Cost of Owning a Car Per Month UK
Understand where road tax fits into the wider monthly cost of owning a car.
EV Charging Cost Calculator UK
Estimate electric charging costs before comparing total ownership cost.
Cheapest Cars to Run UK
Compare car choices where total running cost matters more than one tax figure.
How to Reduce Car Running Costs UK
Cut tax, fuel, insurance, maintenance and ownership costs where possible.