Useful next calculations
Rates and sources
DVLA, HMRC fuel advisory rates and manufacturer-published figures. Real-world results vary by driving style.
Source: DVLA / HMRC fuel advisory rates. Check the linked guidance and any live quote before acting.
When to use this calculator
- When you need a fast estimate before making a bigger decision.
- When you want to compare a few scenarios using the same assumptions.
- When you need a clearer starting point before using a detailed quote or formal document.
- When you want to sanity-check a figure you have seen elsewhere.
A worked example
These are the example figures the calculator opens with.
| Input | Value |
|---|---|
| Current Value (£) | £20,000 |
| Annual Depreciation (%) | 15% |
| Years | 3 |
For those figures the calculator returns:
- Value after 3.00 years: £12,282.50
- Lost: £7,717.50 (38.59%)
Method & assumptions
This calculator estimates how much value your car is likely to lose over time using a declining-balance depreciation model, which more accurately reflects real-world used car pricing than a simple straight-line approach. You enter the purchase price, estimated annual depreciation rate, and the number of years you plan to own the car. The calculator does not factor in mileage, condition, regional market variations, or sudden shifts in demand (such as those affecting diesel cars after emissions regulations tightened). Treat the result as a planning guide rather than a precise valuation. For a current market value, tools such as CAP HPI or Parkers provide data-driven used car pricing specific to your registration.
Common mistakes
- Using optimistic assumptions without testing a more cautious scenario.
- Comparing outputs from different tools without checking that the inputs match.
- Treating the result as a final quote instead of a planning estimate.
- Rounding inputs too aggressively.
What to do next
- Try at least one more scenario so you can compare a realistic range.
- Use the related calculators below to cross-check the decision from another angle.
- Write down the key outputs from your best scenarios before you decide.
- If the result surprises you, change one input at a time to isolate the driver.