Total cost of ownership: what 3- and 5-year TCO numbers actually include
The five components of UK vehicle TCO (depreciation, fuel, VED, insurance, servicing), how to compare two cars fairly, and the headline-price trap that makes a cheap car the expensive one.
Look beyond the price. Own the numbers.
- See the real costHeadline price is the worst single number to buy on.
- Depreciation dominatesOn most cars it outweighs fuel, tax and servicing combined.
- Three years is the sweet spotYou skip the steepest years and halve the annual depreciation.
- Assumptions decide itMileage, MPG and horizon can flip which car wins.
- Compare like with likeOne number, directly comparable between vehicles.
The five components
Every honest TCO is the sum of five things over the ownership period. Sum them over 36 or 60 months, divide by the period, and you have a figure that is directly comparable between vehicles.
1. Depreciation
What the car is worth at the end, subtracted from what you paid at the start.
2. Fuel or electricity
Annual mileage divided by MPG, multiplied by the current pump price. For EVs, kWh per mile at your electricity rate.
3. VED (road tax)
The annual charge, set by first-registration date, CO₂, fuel type and list price.
4. Insurance
Your annual premium for the cover you actually carry.
5. Servicing and maintenance
Scheduled services, plus a realistic budget for tyres, brakes, MOTs and consumables.
Some calculators add a sixth: finance interest. Paying cash, that line is zero. On HP or PCP, the interest paid over the term belongs in the TCO: it is a real cost of ownership.
Depreciation: usually the biggest line
For most cars, depreciation is bigger than fuel, tax and servicing combined.
The rough UK pattern, from new
- Year 115–30%The drive-it-off-the-forecourt hit.
- Year 210–15%
- Year 38–12%
- Year 45–10%
- Year 5+3–5% a yearFlattening as the car ages.
By year five most mainstream cars are worth 35–45% of their new price. Premium brands hold more (a five-year-old BMW retains around 50%) and discount brands less, though the smaller drop starts from a much lower price.
Why a three-year-old car is the sweet spot
Bought new at £25,000
- End of year 1: £19,000
- End of year 5: £10,500
- £14,500 lost over five years
£2,900/year
Bought at 3 years for £14,000
- Kept a further five years
- Worth £6,500 at year 8
- £7,500 lost over five years
£1,500/year
Less than half the annual depreciation. This is why the cheap-on-paper car can be the expensive one: high depreciation on a low headline price still eats more annual cash than low depreciation on a higher one.
Fuel: the line that varies most by use case
Simple in principle, devastating to get wrong on assumptions.
annual miles ÷ MPG × 4.546 × pump price per litre
The 4.546 converts UK gallons to litres.
12,000 miles at 45 MPG
£1,879/yr
Same usage at 35 MPG
£2,416/yr
A 10-MPG difference
£2,685 over 5 years
The MPG claim is a lab figure
The spec sheet quotes WLTP combined, a controlled-lab average. Real-world MPG in mixed UK driving is usually 5–15% lower. Diesels come closer to the claim on motorways; petrol hybrids over-deliver in town and underperform on motorways.
Mileage estimates run low
People remember the commute and forget the weekends. The UK average is 7,400 miles a year, but city commuters typically hit 10,000–12,000 before leisure. Budget high: over-running adds £500–£800 you did not plan for.
For EVs, the same formula
Using kWh per mile and your electricity price. Charging at home on a cheap overnight tariff (~£0.10/kWh) costs roughly a third of a petrol car. At rapid chargers (~£0.80/kWh) it is similar to petrol or slightly more. Mixed use sits between.
VED: road tax
The most predictable line in the TCO, because the government sets it explicitly.
- Petrol or diesel, post-2017£195 / year
- Hybrids, post-2017£185 / year
- Electric, from April 2025£195 / year
- Cars over £40,000 list+£410 / year, years 2–6
- Diesels registered Apr 2017 – Apr 2020, non-RDE2+£30–£150 / year
- Standard vans£345 / year
- Motorbikes, by engine size£26–£121 / year
Cars registered before April 2017
VED is set by CO₂ band on the old system, and the same band lookup applies for as long as the car stays on the road. A 2014 Focus 1.6 diesel sits in Band C at £20 a year; a 2014 BMW 320d, with slightly higher CO₂, sits in Band E at £150.
Some calculators ignore VED entirely. That is a £200–£700 a year underestimate on any non-EV car.
Insurance: the most personal line
The line where two buyers of the same car can have wildly different costs.
Driver age
A 19-year-old pays roughly 4× what a 35-year-old pays for the same car.
Postcode
Inner London, Manchester and Glasgow run 50–100% above rural postcodes.
No-claims discount
Five or more years knocks 60–70% off.
Insurance group
A group 5 hatchback insures for half what a group 35 hot hatch does.
Annual mileage
Lower declared mileage means a lower premium, but understating it voids the policy.
Modifications
Even aftermarket alloys or lowered suspension can add 20–40%.
A calculator can only estimate from the vehicle's insurance group and an assumed driver profile. Treat it as a comparison baseline between cars, not as your premium; then get three real quotes for each shortlisted vehicle. If Car A is group 12 and Car B is group 28, expect B to run 40–60% higher for the same driver, year after year.
Servicing and maintenance
The line most people forget. A realistic UK budget averages £600–£1,200 a year.
- Annual minor service£150–£250 independent, £300–£500 main dealer
- Major service, every other year£350–£600 independent, £600–£900 main dealer
- Tyres, a full set every 25–40k miles£400–£700
- Brake pads every 25–40k miles£150–£250
- Brake discs every 60–80k miles£250–£400
- MOT£54.85, the maximum statutory fee
- Wipers, bulbs, screenwash, AdBlue£50–£100 a year
Premium German brands typically run 30–50% higher on parts and labour. Older cars need more: failing electrics, worn bushes, exhausts.
EVs trim some of this (no oil, no spark plugs, less brake wear from regen) but less than the marketing suggests. Tyres often wear faster on heavier cars, and 12V batteries, cabin filters and brake fluid still need doing.
A worked TCO comparison
Two cars at the same dealer, both 2021 with 30,000 miles. All figures are annual unless marked.
| Line | Car A · petrol, 45 MPG, group 14 | Car B · hybrid, 60 MPG, group 18 |
|---|---|---|
| Purchase price | £14,000 | £17,500 |
| Fuel (12k miles, £1.55/litre) | £1,879 | £1,410 |
| VED | £180 | £170 |
| Insurance | £800 | £900 |
| Servicing | £700 | £750 |
| Depreciation | £1,200 | £1,300 |
| Annual TCO | £4,759 | £4,530 |
Car A wins over five years
Car B is £3,500 more expensive on day one but £229 a year cheaper to run. Over five years those savings recover only £1,145 of the £3,500 difference, so the cheaper car really is the cheaper car, on this horizon.
Change the assumptions and it flips
Move to a seven-year horizon, push fuel to £1.70 a litre and raise the mileage to 15,000, and Car B catches up. Depreciation rates flatten, fuel cost amplifies, and the hybrid's MPG advantage compounds. TCO is sensitive to the assumptions: always check the calculator's match your reality.
Illustrative example. Your mileage, insurance, fuel price and service costs will change the result.
Look beyond the price. Own the numbers.
A 3-year and 5-year TCO is computed for every listing from your declared annual mileage, current UK pump prices and electricity rates updated quarterly, the vehicle's WLTP combined MPG (or the manufacturer's combined figure with a 12% real-world discount), the right VED basis for its registration date, an insurance estimate scaled by your postcode, and a servicing budget derived from age, mileage and category.
- TCO shown on every listing card beside the price
- Fuel costed against your own annual mileage
- VED by registration date, not a flat guess
- Insurance scaled by group and home postcode
